Methods and apparatus to detect and warn proximate entities of interest

ABSTRACT

Systems and methods to detect and warn proximate entities of interest are described herein. An example signal generation system for a vehicle capable of different modes of movement includes a detector to determine at least one property of vehicle movement and an output representative of that at least one property and a selectively variable signal generator includes an input to receive the at least one output representative of the at least one property of vehicle movement and, responsively, generates a selected signal based on the received output. In some examples, a detector on a pedestrian detects the selected signal from the signal generator and, responsively, provides an output indicative of a vehicle in proximity to the pedestrian. In some examples, a trajectory vector is generated for at least two entities of interest based on at least one characteristic of movement of each entity. Each entity&#39;s trajectory vector is expanded and each entity&#39;s expanded trajectory vector is analyzed for overlap with the other entity&#39;s expanded trajectory vector to assess the possibility of a collision between them.

FIELD OF THE DISCLOSURE

This disclosure relates generally to loading docks and, moreparticularly, to methods and apparatus to detect and warn proximateentities of interest.

BACKGROUND

There are many environments where enhancing worker safety is desirable.Examples of such environments include loading dock areas, warehouses,distribution centers, and similar facilities. In addition to such placesusually being crowded, noisy and full of activity and otherdistractions, the juxtaposition of people and vehicles (fork trucks,pallet jacks, etc.) greatly increases the potential dangers. People andheavy, moving vehicles do not consistently interact this way in otherenvironments (e.g. on the street with defined lanes/roads for vehicles,sidewalks and crosswalks for pedestrians, stop signs, stoplights, etc.),but it is currently the status quo in the enumerated environments. As aresult, accidents in which individuals are struck by forktrucks, andsimilar and related accidents, are all too common.

Several factors can increase the likelihood of such accidents occurring.One factor is the crowded, busy, noisy, distracting environment referredto above. The presence of such distractions can prevent an endangeredindividual from realizing and reacting to a dangerous situation.Ironically, one source of such distractions are the myriad lights,strobes, horns and/or buzzers intended to warn against such dangers.Another factor is the presence of blind spots. An individual walkingdown an aisle in such a facility is not able to see potential dangersaround the corner at the end of the aisle, or at a mid-aisle break. Theway forktrucks are used to load and unload trucks parked at a loadingdock also create blind spots for a driver of the forktruck. Typically, afork truck is driven forward into a trailer, and then driven in reverseto depart the trailer. While swiveling seats and/or fork truck mountedmirrors are used in attempts to minimize this problem, these attemptedsolutions are not completely satisfactory. Indeed, an individual thatspends any significant amount of time in such a facility typicallyadopts the practice of stopping and looking into each trailer parked ata loading dock as he traverses from dock to dock—for fear of beingstruck by an inattentive or blind-spotted backing fork truck.

The current mechanisms for preventing or minimizing the severity ofthese kinds of accidents generally fall into two categories. The firstcategory is personal safety items—typically some sort of apparel. Commonexamples include hard hats, safety glasses, steel-toed shoes or bootsand safety vests. Most of these apparel items are intended to minimizethe effect of such an accident. A hard hat, for example, can cushion butnot prevent a blow to the head. Some safety vests are intended to helpin preventing accidents, as they can be made of highly reflective orbrightly-colored fluorescent material to increase the visibility of thewearer so they can be seen by a fork truck driver or other source ofhazard. In general, these safety items are limited in theireffectiveness in that they are passive. On the other hand, they doprovide the benefit of being worn by and traveling with the person beingprotected.

Besides such personal safety or apparel items, the other category ofdevices intended to prevent or minimize these kinds of industrialaccidents are warning systems. Typically, some kind of warning/signalingdevice (a red light, a flashing light, a strobe light, a horn, a bell, abuzzer, etc.) is activated in response to the detection or sensing of adangerous condition. Such sensor-responsive signaling may include alight being illuminated when a piece of equipment is turned on. Othersignaling might be activated by the detection or sensing of a dangerousoperational condition of a piece of equipment, such as the signaling ofmovement of a piece of equipment representing a hazard (e.g. a backupbeeper for forktrucks). Another example loading dock safety device knownas a vehicle restraint is intended to engage the Rear Impact Guard (RIG)of a trailer parked and being un/loaded at the loading dock to preventthe dangerous condition of the trailer departing from the dock whilebeing un/loaded. In such loading dock safety devices, a sensingmechanism is employed in an attempt to determine if the RIG had indeedbeen captured by the restraint. If so, a light inside the dock isilluminated green to indicate that the trailer is restrained and can besafely un/loaded. If, however, the sensor does not detect capture of theRIG, and inside red warning light is illuminated and/or a horn sounds tosignal that it is unsafe to un/load the trailer. Other forms of vehiclerestraints are designed to engage other structure on the vehicle such asthe wheels, the chassis, the bogey rail, etc.

Systems also exist to attempt to warn either pedestrians or proximatefork trucks of imminent collisions between the two. While a variety ofsensing technologies have been coupled with warning signaling, suchsystems do not fully or effectively address the situation. For example,the warnings they provide may suffer from a lack of specificity. Thislack of specificity may be in regard to what the hazard is. A givenfacility can have so many lights, horns and sirens that it may bedifficult for an endangered individual to properly associate a givenwarning with a given threat. The lack of specificity may also relate towho is in danger. If, for example, a sensing system is intended todetect when a person has entered into a large, designated area, severalpeople in close proximity to the area may hear or see a warning and mayall be under apprehension of danger based on that warning signal, eventhough only one of them has actually breached the area. Given thisexample, a more likely result is that all of the individuals will ignorethe warning as it is unable to specify who is in danger. The lack ofspecificity may also apply to the location, direction, or distance (ineither physical distance or temporal distance) of the impending hazard.Relatedly, the timing of the hazard may be imprecisely conveyed by thewarning used—with the endangered individual not knowing if there is ageneralized threat that may occur at any time, or if a given threatenedharm is imminent. This unduly limits the opportunity for the threatenedindividual to take appropriate avoiding or remedial action relative tothe threat. Additionally, an imprecise and/or constant apprehension ofdanger may result in the loss of productivity of the affected personnel.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example system having an unmodulated warning zone.

FIGS. 2A and 2B illustrates an example system having a modified warningzone.

FIGS. 3A and 3B illustrate an example system having another modifiedwarning zone.

FIGS. 4A and 4B illustrate an example system having yet another modifiedwarning zone.

FIG. 5 illustrates an example graphical display of an example systemdescribed herein.

FIGS. 6A and 6B illustrate an example proximity-based detection systemdescribed herein using visual light to create a warning zone.

FIG. 6C is a flowchart representative of example machine readableinstructions that may be executed to detect a particular hazard indifferent areas of a building.

FIG. 7 illustrates an example facility implemented with an examplesystem described herein.

FIG. 8 is a flowchart representative of example machine readableinstructions described herein that may be executed to implement anexample system described herein.

FIG. 9A illustrates an example vector-based trajectory of two entitiesof interest.

FIG. 9B illustrates an enhanced example vector-based trajectory of thetwo entities of interest shown in FIG. 9A.

FIG. 9C is a flowchart representative of example machine readableinstructions that may be executed to implement a hazard discriminatorthat performs a predictive analysis.

FIG. 10A illustrates a warning zone provided by another example systemdescribed herein.

FIG. 10B is a flowchart representative of example machine readableinstructions to generate a warning signal based on a modified safetyzone.

FIG. 10C is a flowchart representative of example machine readableinstructions that may be executed to determine the possibility of acollision between entities of interest.

FIG. 11 illustrates an example loading dock area implemented with anexample system described herein.

FIG. 12 illustrates example eyewear that can be communicatively coupledto an example system described herein.

FIG. 13 illustrate an example hard hat and example bracelets that can becommunicatively coupled to an example system described herein.

FIG. 14 illustrates an example vehicle implemented with lights toprovide a visually conspicuous warning zone adjacent a perimeter of thevehicle.

FIG. 15 illustrates another example hard hat implemented with aplurality of warning modes.

FIG. 16 illustrates yet another example hard hat implemented with aplurality of warning modes.

FIG. 17 is a block diagram of an example processing system that mayexecute the example machine readable instructions of FIGS. 6C, 8, 9C,10A and 10B to implement the example systems described herein.

DETAILED DESCRIPTION

A first category of sensing systems to detect or sense potentiallydangerous interactions between forktrucks and pedestrians (or othervehicles, people or equipment in a facility) uses detection or sensingtechniques based on proximity. In general, the sensing technologydetects and/or determines when a potentially dangerous condition existsbased on the proximity of, for example, a potentially harmed entity (apedestrian) and a dangerous instrumentality (e.g. a blind intersection,or a forktruck). As used herein, such potentially dangerous (ordangerous in fact) situations will be referred to collectively as“threats”. For example, a sensing system can determine threats at afixed location such as a blind intersection. A first example system usestwo ultrasonic sensors located at a corner—one orientated in a firstdirection or “field of range” of an approach, and the other orientatedin a second direction or field of range different from the firstdirection or field of range. When the system detects bodies or entitiesof interest on both fields of range, a generalized warning is given. Thedetection is based on the time delay between sending the ultrasonicsignal and receiving the reflected signal from a body. In anotherexample, a system includes a sensing apparatus mounted above anintersection to scan or look down the aisles approaching theintersection (e.g., four aisles, three aisles, etc). Detection of anapproaching object that is large enough (i.e. not pedestrians) causes awarning. The system can discriminate between approaching and retreatingobjects. Another example system uses photoeyes mounted near potentiallydangerous locations in combination with reflectors or reflective tape onthe forktruck. Passage of the forktruck triggers the photoeye indicatingproximity of the forktruck to the potentially dangerous location andtriggers general warnings. However, the current array of generalizedwarning and threat-communication systems have limited utility in thiscritical function of preventing or minimizing these potentially veryhazardous industrial accidents. In these cases, of course, the warningis only generalized, and indicative of a potentially dangerouscondition. Even so, such systems could have some application to moreeffective threat detection and communication. For example, aparticularly dangerous area is the area surrounding a dock leveler whena truck is being loaded or unloaded, since forktrucks departing thetruck are traveling in reverse or backward, and the operator may nothave adequate sight lines to see pedestrians in the area. A systemcapable of determining that 1) a forktruck is in the trailer (or evenleaving the trailer if a directionally-discriminatory system is used) iscombined with a means for determining the presence or approach of apedestrian to the dangerous area around the leveler to trigger awarning. This warning is specific in terms of indicating that aforktruck is coming out of the trailer. Additionally and alternatively,the warning is personally directed to the person approaching harms way.Such solutions are disclosed in a co-pending US Patent Application,Publication Number 2008/0127435, which is incorporated herein byreference in its entirety.

There exist many examples of proximity sensing systems for movingobjects such as forktrucks relative to hazards such as pedestrians. Insome such systems the potentially endangered personnel are provided withsome form of detector that can determine the signal strength of a signal(typically an RF or other electro-magnetic signal) sent by the dangerousinstrumentality (e.g. a forktruck). Detection of a sufficient signalstrength causes an alarm, as it is indicative of the dangerous proximityof the forktruck. Several forms of electromagnetic radiation are usedfor this type of ranging system. In one known system, a rotatinginfrared beacon is placed on top of the forktruck, and infrareddetectors are placed either in fixed locations or on moving personnel.When there is close enough proximity of the beacon and detectors totrigger detection, warnings are generated.

In another example, a magnetic field is generated by a field generatoron a hazardous mobile machine, and pedestrians carry detectors fordetecting the presence and strength of that field. This system has thebenefit of both the transmitters and receivers being wire loops that cancreate magnetic fields for applied current, or detect magnetic fields togenerate detectable current. An example use of RF signals includes bothpedestrians and the dangerous instrumentality having transceivers.Further, a signal processing unit on the hazardous mobile machinedetermines the distance of a pedestrian (in one of three ranges based onsignal strength) and is in communication with a control unit thatcontrols certain hazardous aspects of machine operation based on theproximity of the pedestrian relative to the machine. Such functionalitycould apply to the systems of this disclosure, in those aspects offorktruck operation could be controlled based on data about theproximity of pedestrian or other hazards relative to the hazardousmobile machine. This could be particularly beneficial in the context ofpotential collisions occurring around “blind corners”—since anarea-generalized warning might not reach the affected pedestrian—slowingor stopping the forktruck for a perceived hazard could be beneficial.Another RF based system uses a tuned optical transmitter to create acone-shaped warning zone below a moving hazard. Another system uses anRF signal on the dangerous equipment to send an interrogation signal.Any pedestrian receivers in appropriate range (based, for example onsignal strength) send back their identification (ID) associated withthat particular receiver or pedestrian. A processor keeps a table ofauthorized and unauthorized ID's within the safety zone of the machine.For authorized workers, no action is taken—for unauthorized workerswarning signals are generated on the vehicle and sent to the endangeredindividual. This approach seems beneficial for eliminating some“nuisance” aspects of warning people who do not need to bewarned—although making that discrimination would require processing aswill be discussed below. Another example RF based system enables thedangerous instrumentality to transmit different signals (to be detectedby affected pedestrians) for different threats, which differing signalscan be discriminated by the pedestrian receiver, and which can result indifferent warning (audible, visual, tactile) for different threats.

Several of the examples referenced above disclose modifying the signalbeing generated by the dangerous or hazardous mobile instrumentality toconvey more threat-specific information. An application of this exampleis shown in FIGS. 2A and 2B which disclose changing a shape of atransmitted warning signal from a forktruck based on the mode ofoperation or movement of the forktruck, for example, a gear selection ofthe forktruck (e.g., forward, reverse, neutral). An indication of thegear selection from a detector is provided to a transmitter carried bythe forktruck itself, which creates and/or transmits a proximity signalthat will be received by a receiver carried by a pedestrian, whichreceiver is capable of determining the signal strength of the receivedproximity signal. The detector, for example, may include a sensor todetermine a property of vehicle movement such as, for example, whetherthe forktruck gear selector is in the forward position, neutral positionand/or the rearward position and produce an output or signalrepresentative of the vehicle movement property (e.g., the gear selectorbeing in the forward position). The signal is modulated or generatedbased on that gear selection (and/or other indication of activity suchas movement) of the forktruck so as to create an output or warning zoneindicative of the mode of movement or the direction the forktruck istraveling. FIG. 1 shows an unmodulated warning zone 10 that has acircular cross section since the transmitter generates a field thatradiates in all directions. As seen in the FIGS. 2A and 2B, a warningzone 10′ is biased toward the front of the forktruck when it is movingforward, and biased to the rear, when the gear selector is in reverse.This may help avoid nuisance alarms—for example to a pedestrian who ispositioned behind a forktruck that is moving forward. As used herein,the terms transmitter and receiver should be broadly construed toencompass at least the various forms of radiation (magnetic, RF,optical, infrared, etc.) described above and below.

Similarly and relatedly, the proximity signal generated by thetransmitter on the forktruck is modulated by the speed and/or travelingdirection of the forktruck to dynamically modify the shape of theproximity signal's “field” or warning zone. A faster-moving forktruckcreates a larger zone, a forward-moving forktruck creates a zone shapebiased to the front of the forktruck, and vice-versa for a backingforktruck. Such an example is depicted in FIGS. 3A and 3B, with FIG. 3Ashowing the warning zone 15 for a relatively slow-moving forktruck, andFIG. 3B showing the warning zone 16 for a relatively fast-movingforktruck. For a pedestrian outside either warning field of FIGS. 3A and3B, but being approached by such forktrucks, the field or warning zoneof FIG. 3B would result in receiving the signal earlier and with arelatively larger signal strength as compared to that of the signal fromthe slower-moving forktruck as in 3A.

The example of modulating the “warning field” for a forktruck based onoperational parameters such as gear selection or relative speed isenhanced by using the position of the forktruck steering wheel as thesource of such modulation. Forktrucks may be particularly dangerous byvirtue of the fact that they are steered by the rear wheels as opposedto the front wheels as we are commonly used to from other vehicles(e.g., automobiles, etc). Accordingly, the movement or steering actionof a forktruck can be potentially dangerous to an unsuspectingpedestrian. Modulating the “warning field” of a forktruck based on thesteering wheel position or rotational direction can provide effectivewarning signaling to a pedestrian unfamiliar with this movement. Asensor monitors either the absolute position of the steering wheel, orthe direction it is being rotated, and the shape or orientation of thewarning field is modified based on that signal. In the example of FIG.4A, a forktruck warning field 20 that is not modulated by a steeringsignal is shown. The curved arrow 30, and the straight arrow 40 indicatethat when the forktruck is turning to the driver's right, the steeredrear wheels will actually swing toward the depicted pedestrian (to thedriver's left) who may not be familiar with this unusual motion. In theexample of FIG. 4B, however, the warning field 20′ is shown in both a“normal” orientation (extending in a forward direction from theforktruck), but also in a counter-clockwise rotated orientation due tothe fact that the forktruck steering wheel has been turned to the right(meaning the rear wheels will be turning to the left). The modulatedwarning field may include only the second, rotated lobe or both. Inaddition, the warning zone may include a third lobe directed in aclockwise orientation relative to the forktruck to warn someone forwardof the vehicle of the impending turn. Rather than the warning signalbeing divided into lobes (which is done here for purpose ofillustration), a single field shape could be used to provide anindication of the soon-to-result turning movement of the forktruck. Themodulation of the warning field for a turning forktruck may be performedin advance of the actual movement to give a prospective quality to thewarning by using the rotational position and the rotational speed of thesteering wheel as a modulation signal. An alternative is to provide theforktruck with a turn signal switch such that activation of the rightturn switch by the forktruck operator (trained to activate the switchseveral seconds before initiating the turn) would serve as the triggerfor modulating the warning field in the manner of FIG. 4B. Thus, systemsor sensing apparatus to modulate a proximity-based signal withthreat-relevant information (e.g. the status of the forktruck gearselector, or its speed or direction) to allow more effective warningbased on that threat-relevant information are disclosed herein.

Additionally or alternatively, the modulation of the proximity signalnot only changes the shape of the field, but also encodes additionalinformation. For example, if the field is modified according to thespeed of the forktruck, the speed is encoded into the modulated signal.A detector/receiver configured to detect and/or receive the presence ofthe signal and also decodes the speed of the approaching hazard, therebyproviding threat-relevant information that is used to appropriatelymodify the warning signal (e.g., different levels of warning fordifferent levels of threat). In another example, the proximity signalcan be configured to convey information about the hazard to multipletransmitters on the forktruck, for example, one facing in the forwarddirection and one facing in the backward direction. The two transmitterssend different proximity signals, both of which could be received by apedestrian receiver or detector. The detector may provide an outputindicative of a vehicle in proximity to the pedestrian. An output may bedecoded or generated as a warning signal of a forktruck approaching ineither a forward or rearward direction. Given the sight-line limitationsimposed on a forktruck driver while traveling in reverse (backing up), apedestrian detection of the rearward direction signal could create amore urgent warning than detection of forward movement direction signal.Modulation of the proximity signal to indicate speed could also beachieved by increasing the repetition rate of the proximity-detectingsignal with speed. Instead of a constant field being emitted, bursts areemitted, and the burst rate increases with vehicle speed. The detectorwould thus be able to determine based on the burst rate how fast theforktruck was approaching. If desired, different warning signaling fordifferent speed ranges could be provided to the pedestrian.

The proximity-based systems described so far generally utilize or relyon signal strength for determining the existence or level of a threat.While such proximity can be useful information to a threatenedpedestrian, proximity-based systems can be enhanced by adding acomponent of directionality by providing both distance and directionalinformation between a dangerous instrumentality and apotentially-affected pedestrian. In an example of such a system, aforktruck includes a Directional Antenna Array comprised, for example,of three separate antenna spaced at a known distance and orientation.The array allows shaping of an interrogation signal that will be sentout by the forktruck to any pedestrian transponders in range. Thatshaping is indicative of the direction, speed, and/or other property ofthe forktruck, along the lines referred to above. Receivers or detectorscarried by pedestrians (illustratively in the form of portable badges)are capable of detecting the interrogation signal and responding (again,perhaps only when the interrogation signal is of adequate strength). Theresponsive signal is received by the array, where the multiple antennasallow directional resolution of that received signal via, for example bytriangulation, or other similar techniques known to those skilled in theart. Combining such directional information with a technique fordetermining distance (e.g. measuring the time delay between transmissionof the interrogation signal and receipt of a responsive signal withinsome maximum allowed time range to avoid nuisance detections), allows aprocessor associated with the system to determine the position of thepedestrian with some specificity since one would know its distance anddirection. The determined location of pedestrians (or other objects orhazards capable of having transponders) is then displayed to theforktruck operator on a graphical display, as shown in FIG. 5. Thegraphical display of FIG. 5 shows the forktruck FT and potential hazardssuch as, for example, circles P representing pedestrians and squares Frepresenting other forktrucks. Processing the position informationreceived relative to the forktruck can also used to providethreat-specific warning to the forktruck operator (e.g. a auditorywarning of the direction and distance or time to potential collisionwith the detected pedestrian), or take corrective action (e.g. applyingthe forktruck brakes to prevent collision). Given the existence of acommunication channel, the processor can also formulate and sendthreat-specified warning to the affected pedestrian (for example,different levels of warning based on the proximity and/or direction ofthe forktruck) and have discrimination so as to avoid warning unaffectedpedestrians (e.g. not warning close-by pedestrians that the forktruck ismoving away from them).

Another example of a proximity based detection system for hazards usesvisual light to create a warning field that can be detected by sensors,but that is also visible to the eye. As depicted in FIGS. 6A and 6B, aforktruck FT is fitted with one or more light sources 40.Illustratively, four light sources (front, back, left and right) areprovided, with the capability of projecting both red and green light.For normal operation of the forktruck (i.e. when it is driving in agenerally forward direction through the facility with no detectedhazards), the forward light source 40 is illuminated green to project acone-shaped signal 50 on the floor in front of the forktruck. In thiscase, the front light is illuminated as the forktruck is moving in aforward direction. Alternatively, a different shape is used for theforward signal including a forward signal the shape of which ismodulated by the speed of the forktruck (as in previous examples, theshape would extend further forward or be larger in the forward directionfor a faster forktruck speed in that direction). One way to achieve thismodulation is to provide the light sources 40 with adjustable apertures,lenses and/or adjustable positioning so that the shape and direction ofthe light sources can be modulated based on inputs from other sourcessuch as, for example, a speed and direction indication received from theforktruck, although other sources could be used. In another alternative,shown in FIG. 6B all of the light sources are illuminated green in thiscondition of the forktruck moving generally forward through thefacility, in effect creating a “zone of safety” around the forktruck.The green illumination (either only in the forward direction, orsurrounding the forktruck, or taking other shapes) serves as a visualindication to the forktruck driver that the path he is pursuing is“safe” (no pedestrian interactions have been detected), and also as avisual indication to surrounding pedestrians that the path of theforktruck is “safe” insofar as close-proximity pedestrians have not beendetected. The projection and ability to perceive these “light signal”may be enhanced by painting the floor of the facility with a reflectivepaint, or by adding reflective grit to the concrete floor when poured.

The light projected from the source(s) 40 can serve the dual function ofnot only providing signaling, but also of being a warning field that canserve as the basis of proximity-based sensing of hazardous conditions.As one example of such a system shown in FIG. 6A, the workboots 60 ofthe pedestrians in a facility are fitted with light sensors 62 that aredesigned to detect light of a specific wavelength or wavelengths andabove a designated intensity. In this example, the detectors aredesigned to detect the green and red lights projected by the lightsources 40 of the forktruck FT of FIG. 6A. Accordingly, if a forktruckprogressing through the facility gets close enough to a pedestrian (orother hazard, such as a similarly equipped stationary object) to bepotentially dangerous, the light sensor 62 will be activated by thelight from one or more of the light sources 40. This activation canserve as the source of a properly formulated warning signal to theaffected pedestrian such as an audible warning that there is a forktruckin close and potentially dangerous proximity. In an enhanced system ofthis kind, pedestrians and forktrucks are fitted with communicationdevices to allow signaling between them. In such a system, the detectionof the warning field by the light sensor 62 would also result in asignal being sent to the forktruck indicative of a pedestrian inpotentially dangerous close proximity. The receipt of such a signalwould then cause some or all of the light sources 40 on the forktruck toturn to the red color, thus projecting a red color on the floorsurrounding or adjacent the forktruck. This red color serves as a visualindication to the forktruck driver of a potentially hazardous situation.Moreover, it serves as an additional visual signal to the affectedpedestrian (or other pedestrians in the area) that a dangerous conditionexists. Since the warning field now surrounding or adjacent to theforktruck is red, and because the light sensors 62 illustratively in theworkboots of the pedestrians can also detect red, such detection bysensors 62 may be indicative of an imminently dangerous situation (sincethe changing of the light warning field to red was already triggered bya detection of a pedestrian within some predefined unsafe proximity).The result of such detection would then be a specialized warningintended to convey the immediacy of the threat as opposed to a moregeneralized warning to raise the pedestrian's awareness. Similarly, ifthe detection of the red light by a light sensor on the pedestrian iscommunicated to the forktruck, action could be taken such as flashingthe warning field surrounding or adjacent to the forktruck to provide avisual indication to forktruck driver and pedestrian alike of theimmediacy of the danger.

The examples described above using visible light as the basis of aproximity-based hazard sensing system can be applied or implemented withother systems. For example, a particularly common industrial accident isa forktruck running over a person's foot, which most often happens whena stationary forktruck near a pedestrian begins moving. To address thisspecific situation, a forktruck could be outfitted with light sources 40like those shown in FIG. 6A. In this example, however, the light sourcescould be a single color, or even a non-visible light (e.g. an infraredlight), and would always be projected in a warning field surrounding theforktruck, such as a circular warning field. Alternatively, since thisaccident is most common with a stationary forktruck, the warning fieldcould only be projected when the forktruck is stationary (either bydetecting a lack of motion, or by determining that the gear selector isin the neutral position). In either event, the workboots of pedestriansare equipped with light sensors designed to detect the wavelength oflight projected by the light sources above a given illumination levelindicative of a predetermined unsafe (or potentially so) proximity tothe forktruck. Whenever a pedestrian is close enough to the forktruckfor the warning field to be sensed by the light sensors, a warningsignal may be provided to the pedestrian, the forktruck or both. Thismay be particularly effective if the warning field is only generatedwhen the forktruck is stationary, as receipt of the warning signal bythe pedestrian indicates that he is close to the forktruck, andpreferably raise his awareness of the situation to be cautious about theforktruck beginning to move. As a further enhancement, a communicationchannel between the pedestrian and the forktruck would receive anindication of the light sensor detecting the hazardouscondition—resulting in corrective action. For example, the forktruckcould be prevented from moving if such detection occurs, or a warningsignal could be provided to the forktruck operator of a pedestrian indangerously close proximity. The operator may be able to visuallyidentify the affected pedestrian and override the warning to beginmoving the forktruck, or the system could be latched in a way thatmovement of the forktruck is not possible until the pedestrian movesaway from the warning field of the forktruck (e.g., to a far enoughdistance away from the forktruck) so as to not be endangered by theforktruck then moving.

The signaling aspect of the visible light based system can also beapplied in other ways. While the forktruck projecting light on the floorwas used both for visual signaling and for hazard detection by the lightsensors on the workboots, the example is not so limited. Indeed, theprojection of green and red (or additional color) lights around theforktruck could be applied irrespective of what system is used for thesensing of hazards. Again, such signaling is beneficial in that it canprovide the same indication of hazard, vel non, to both the forktruckoperator within the colored field of light, as well as the pedestrian(or other forktruck operator) without that colored field of light.

The use of color can also be applied in a different way to achieve someof the safety goals of this disclosure. Rather than having a forktruckcarry light sources, however, this example divides a given facility intodifferent zones which have differing safety levels. One zone may be agenerally open area in the middle of a warehouse space where typicallyonly forktrucks are present, and few pedestrians enter. Another zone maybe the loading dock area of a warehouse, where pedestrians andforktrucks typically both reside. A third zone may be a corridor whereforktrucks are present that is just beyond doors into meeting rooms,offices, or other people-only spaces (these can be particularlydangerous corridors). The floor of the different zones are each painteda particular color—chosen to be indicative of the danger level vis-à-visa particular hazard—in this example pedestrian-forktruck collisions.Since the first, open zone described above is generally a low-dangerarea relative to such collisions, the floor of that area may be painteda first color, illustratively blue. The loading dock area or zone is ofa relatively higher danger level, and might thus be painted yellow.Finally, the zone or corridor outside the meeting room area ispotentially highly dangerous and might thus be painted red. It should benoted for the purposes of this discussion that the term “paint” or“painted” should be broadly construed to include not only actual paint,but also, for example adding a coloring agent, such as a colored grit toconcrete as it is poured or any other way to achieve the desired effectof coloring the floor a particular color. The painting or coloring ofthe floor in the various areas thus serves as a visual indication topedestrians and forktruck operators alike about the potential threatlevel in that area. Alternatively, a zone-based indication using colorcould be provided by modulating the colors of overhead lights in thevarious zones, to similar effect.

In addition to providing a visual indication, the floor coloring canalso be used to modify the operation of the forktruck to take thepotential threat level into account. In that regard, the forktruck canbe fitted with a color detector that can detect whether the forktruck isin a “low-danger” blue area, a “raised danger” yellow area, or a “highlydangerous” red area. Based on the type of zone in which the forktruckthen resides, operational parameters of the forktruck can be modified.For example, in a blue zone, no modifications might be made. In a yellowzone, however, a speed limitation may be imposed on the forktruck. In ared zone, the forktruck might become inoperable upon entering the zoneuntil a particular safety protocol is carried out and verified.

The differing zones could also be used to modify the operationalparameters of other systems besides just the forktruck. Differentsensing mechanisms for detecting hazards could be used in differentzones. For example, a robust, sophisticated hazard detection systemmight require large amounts of electrical or computing power to beeffective. If such a system is carried with a pedestrian, powerconsumption is an issue, as a power source such as batteries, and acomputing source such as a processor must also be carried. Accordingly,to limit power consumption, it is desirable to only use this system inhigh-danger areas. If the pedestrian carried a color detector, someexample systems are programmed to only activate and power the hazarddetection system when the pedestrian is in a high danger zone (e.g., thered zone), and to use different hazard detection system(s) in lessdangerous zones (e.g., the blue zone). Some examples apply the sameapproach to the forktrucks or to providing warnings in which differenttypes of warning are presented to potentially endangered actorsdepending on which level zone the actor is in. It is also the case that“zones” could be established in other ways besides the coloring of thefloor in given zones. Generally, zones may be provided in a facilityaccording to the potential danger related to specific events (such asforktruck-pedestrian collisions), and that operational protocols, hazarddetection schema, threat communication schema, etc., can be modifiedbased on the zone of activity or interaction.

FIG. 6C is a flow diagram representative of example machine readableinstructions 6000 that may be executed to implement a system to detectand/or warn of hazards in different ways for different areas of abuilding. At block 6002, the system determines threat levels for ahazard in respective ones of different areas of a building. For example,the different areas may be “highly dangerous” areas, “relatively lowdangerous” areas, etc. This determination can be made based onhistorical data (e.g., number of accidents in a given area), empiricaldata (e.g., types of locations that are expected to have heightened riskof collision), or on manual input (e.g., rankings) Irrespective of howthe threat levels are assigned to areas, the system assigns two or moredifferent hazard detection systems for use in different areas of thebuilding (block 6004). For example, a first detection system may have afirst ability to detect a particular hazard and a second detectionsystem may have a second ability different from the first ability todetect the particular hazard (block 6004). For example, the firstdetection system may be a robust, sophisticated hazard detection systemto be used in building areas identified at block 6002 as relatively highdanger areas and the second detection system may be a less sophisticated(and likely less expensive in costs and/or computing resources) hazarddetection system that may be used in relatively low danger areas asidentified at block 6002. Once the systems are deployed in accordancewith the assignment made at block 6004, the system employs the firstdetection system to monitor for the particular hazard in a first areaassigned a first threat level (block 6006), and the system employs thesecond detection system to monitor for the particular hazard in a secondarea assigned a second threat level (6008). In some examples, the systemmodifies the operational parameters (e.g., limit the speed) of aforktruck based on the area in which the forktruck is located (block6010). For example, when entering the first area (e.g., an areaconsidered to be a relatively high threat area), the robust firstdetection system may have the ability to automatically enforce a speedlimit via an electronic control signal on the forktruck or may send asuitable warning to the forktruck that it is in a high danger zone.

At block 6012, the system determines if it is time to reassess the zonethreats assigned to the areas. If so, control returns to block 6002. Ifnot, control advances to block 6014.

At block 6014, the system determines if it has received a command toshut down. If so, the instructions of FIG. 6C terminate. Otherwise,control returns to block 6006 to continue to monitor for threats.

Any or all of blocks 6006 and 6008 may be implemented by FIG. 4C.

Other ways of determining “zones” of different threat levels can also beemployed. For example, one zone may be considered more dangerous thananother based on population or traffic density—a higher density arguablyrepresenting a greater threat. Creating zones based on populationdensity can be done statistically (such as by monitoring areas over timeand assigning densities to various areas based on the results), ordynamically such that the area of a more dangerous “high density” zonecan change over time to reflect changed circumstances in a givenparameter like population density. There also may be a temporalcomponent to a given zone being considered more or less dangerous. Forexample, an operation that only loads trailers on third shifts, theloading dock may only be designated as a “high risk” zone during thistime, and be designated “low risk” at other times.

At least some of the sensing systems described above rely primarily onsignal strength to determine proximity, and thus the existence of adanger. In some cases, the proximity sensing is enhanced by signalprocessing to indicate direction as well as distance to the hazard. Someprocessing of these signals to discriminate among the level andimmediacy of threat has also been described. Even so, a system relyingon relative position data has potential limitations on resolution,accuracy, timeliness, etc.—although with the advantage of a relativelyinexpensive implementation. A system that would allow more accurate andmore absolute determination of position, direction, velocity, etc. mightprovide a higher fidelity of warning, although likely at an increasedcost in terms of both component cost and system complexity.

Absolute Location Sensing

Other example systems include absolute location technology for enhancingthe determination of proximity of a dangerous instrumentality (e.g.forktruck) and a threatened object or person (e.g. a pedestrian). Insuch systems, both entities typically have the ability to determinetheir absolute location via, for example, Global Positioning System(GPS) technology and/or one or more other technologies. The acronym “AL”will be used herein as a general term for such absolute locationsystems. Knowing the absolute location of both entities allows theirproximity to be determined, and appropriate action taken (e.g. hazardwarning) if that proximity is indicative of a hazardous situation.Accordingly, the first example system described herein are based onproximity (in terms of determining threats) enhanced by AL technology.For example, in one such system, both an earth moving machine andobjects in its vicinity (vehicles, pedestrians) have AL capability. Acommunication channel exists between the machine and the objects throughwhich the objects transmit their self-determined location to themachine. A processor on the machine translates the location informationinto a graphical depiction of the machine and the objects in proximity.The objects can also transmit an identifier, which allows not only theirposition, but an indication of the type of object they are to be shownon the graphical interface. In this case, the operator, armed with thisinformation, is empowered to take appropriate action based on therepresented proximities. This system may also be configured to determinethe accuracy of the position location of the object, and modifying thedisplay based on that information—lower accuracy of position resultingin the object being depicted as larger and vice-versa. Additionally oralternatively, the system can modify the display based on otherinformation about the object. For example, if a unique identifier isprovided by the object, the machine (in this example) could maintainlook-up information (e.g., a look-up table) about that object such as,for example, their authorization to be in certain areas, or in certainproximity to a forktruck, the level of safety training received, whetherthat person is a supervisor or employee with heightened awareness ofhazards, whether that person has been in a high number of accidents,etc. The display could then be modified based on this information, forexample, someone with authorization is depicted as small (since theirauthorization suggests adequate training on safety issues and thus areduced risk relative to other less-trained pedestrians), while thenovice or person prone to accidents would receive a larger icon(indicative of requiring a larger personal safety zone given hisstatus). Furthermore, the system could be enhanced by also providingthreat-specific information about the proximity or potential for dangerback to the affected objects, as will be discussed in more detail belowin the section regarding communication.

Another example system using AL having dangerous instrumentality(typically an emergency vehicle, which is not necessarily dangerous onits own, but is when en route to an emergency and requires a clearedpath) can itself determine the nature of the safety zone it needs tocreate around it (for example, based on its location, speed, direction,course to the emergency, etc.) and broadcasting a signal with suchinformation. Its ability to formulate and broadcast such a message isfacilitated by the presence of an AL system. Accordingly, the broadcastsignal will typically include AL-type coordinates delineating the safetyzone surrounding the emergency vehicle and extending along its projectedpath, on either a temporally static or dynamic basis. The receivingentities also possess AL capability. They thus receive and decode thebroadcast signal, which includes information about the boundaries of thedanger zone, and determine based on their then-current AL positionwhether or not they are in the danger zone. Appropriate action can thenbe taken based on that determination (e.g. a warning signal generated).Given the existence of AL technology in these systems, significantlevels of sophistication are possible. For example, one system showedthe receiving entity as generating specific danger-averting directionsto affected vehicles in the path of an emergency vehicle (“forktruckapproaching from the north behind you, pull to the left and stop”“forktruck approaching you from ahead, proceed with vigilance” etc.). Aswill be described below, such threat-specific warning/direction isdesirable, giving a “personal” aspect of the personal safety zone. Sincethe broadcast warning signal can be created (or modulated) based onthreat-specific information, and since the receivers can be programmedto know their own status and position (based on AL), the sendinginstrumentality can effectively create multiple zones simultaneously. Inthe example of pedestrian/forktruck interaction, the forktruck sendsinformation based on its speed, direction, and course identifying adynamic danger zone. Additionally, the forktruck could also send thatinformation with one threat level for certain kinds of personnel (e.g.managers, supervisors, highly-trained individuals, and/or otheremployees who are authorized to be in an otherwise dangerous localitybased on the current task they are performing), and another, higherthreat level for other personnel. Moreover, the size and shape of thetwo zones just referred to could be chosen to be different—presumably alarger safety zone for less-trained personnel. As mentioned, several ofthese example systems included the ability to take the route to betraveled into account in creating the shape and size of the warningzone. Such functionality is very desirable in the context offorktruck/pedestrian safety as a significant risk in this application iscreated by narrow, blind corridors and corners, for instance betweenracking. If the processing capability on the forktruck can determine oraccount for the racking layout relative to its own current or projectedcourse, that layout (and attendant increased risks) could be figuredinto the logic of formulating the nature of the broadcast danger zone.Further, the broadcast signal could, in appropriate circumstances,include some kind of indication that there is not only a hazard, butthat it involves a blind corner or alley allowing a heightened warningor corrective mechanism to be sent or conveyed to the recipient once thesignal is decoded. Such heightened level warnings are significant inthis application, since the threatened person may not be able toperceive the impending threat even when warned, but a “blind alley”warning could alleviate the problem. Better still is the ability to givemore accurate information about the direction and imminence of thethreat. Providing this, however, could require enhanced processingcapability being carried with the recipient of the signal, which couldbe undesirable given size and power limitations. Compensating for thoserequirements while still giving the desired functionality is desirable.

At least some of the preceding examples included sending instrumentalitythat determined the nature of the threat and the appropriate zone. But,again, with adequate processing power at the location of the recipient,this need not be the case. In another example, two or more entities ofinterest (e.g., two vehicles) may be implemented with AL capability. Thefirst entity of interest sends location, speed, heading, etc.,information. This information is received by the second entity ofinterest, which compares this information with its own (speed, heading,etc.) to determine if there is a risk of collision or other hazard. Insome examples, the first entity of interest corresponds to a forktruckand the second entity of interest to a pedestrian, but in the interestof keeping significant computing needs from the pedestrian, this couldbe reversed. If, for example, each pedestrian had an AL unit, along witha relatively simple accelerometer or other speed/heading-determiningdevice, the AL unit could periodically broadcast this information.Forktrucks would have an adequate power and size platform for thecomputing power necessary to receive such periodic signals, anddetermine based on the position and movement of the pedestrians whetherhazards existed. The forktruck operator could be notified to empower himto take preventative/corrective action. Further, given the existence ofa communication channel, the forktruck could communicate backthreat-specified or otherwise enhanced personalized warning to theaffected pedestrians. As before, if mapping of the facility wereincluded in the programming given to the forktruck, it could takeespecially hazardous situations into account in performing thisfunction, such as pedestrians down “blind” alleys or corners—andappreciate the enhanced danger and take appropriate action or sendappropriate warnings (or both) based thereon.

The examples just described generally rely upon all moving objects (e.g.both pedestrians and forktrucks) having AL capability as well as, insome cases, local processing capability. For example, in the examplesystems where the emergency vehicle sends out a signal via GPS or othercoordinates of the relevant safety zone surrounding it, the vehicle hasthe processing ability on-board to take the AL data and other data (e.g.its route) and calculate the zone shape and size. Similarly, thereceiving object has the processing capability to receive and decode thesignal, and compare the received signal to its own AL-determinedposition. Other systems are possible in which such AL and/or processingcapability need not be present on all mobile objects. For example, acentralized AL system could receive a signal transmitted by the mobileobjects and determine and track the location of all objects. Suchsystems will be described below. Hybrid systems combining these types offunctionality are also possible.

One such hybrid system could be employed using AL capability for someobjects, in combination with a centralized AL system for enhanced systemfunctionality. For example, one such system employs vehicles such asforktrucks which obtain their position by using machine-visiontechnology to decode ceiling-mounted barcodes that they read as theytraverse a facility. The barcodes may be identifying tags (in which casethe location is looked up by the vehicle-mounted system once the ID isdecoded), or they may be tags encoded with the actual positioninformation. In the latter case, the processor on the vehicle decodesthat position information directly by reading the tag. In either case,the vehicle determines its own location in this manner, as well as itsdirection of travel (this being done by calculating, for example, theangular orientation of the read tag and correlating that to a directionof travel). Once this calculation is done (on either a programmed or anon-demand basis), the vehicle wirelessly communicates with a centralprocessor, illustratively equipped to monitor and track the location ofthe vehicle. In an enhanced version, information about the facility (thelocation of walls, racking, etc.) can also be programmed in to thecentral processor, so that the location of the vehicle (and any othervehicles transmitting AL information) can be shown in the context of thephysical facility on an active display (e.g., an LCD display).Additionally or alternatively, the AL information on the vehicles can beused to enhance safety of pedestrians in the facility. This can be done,for example, by creating zones within the warehouse (e.g., presumably inthe software executed by the processor). The processor uses the AL anddirectional information to determine when a vehicle is approaching sucha zone. The system is then empowered to take safety-enhancing actionsuch as illuminating warning lights to warn pedestrians in orapproaching the area that a forktruck is approaching, and perhaps itsdirection of approach. Other safety enhancing action shown is theactuation of safety gates or other barriers to prevent access bypedestrians to the danger zone while the forktruck is in the dangerzone, and/or as the forktruck approaches the danger zone.

Such AL based technology could be used to enhance its functionality andprovide some of the features and benefits of a Personal Safety Zonesystem. One example is to provide pedestrians with the machine visioncapability forming the AL aspects of this approach. In essence, thiswould make both forktrucks and pedestrians visible and trackable in andby the central processor. Software routines could then be written toprocess this data and look for potentially dangerous situations, such ascollisions. As noted above, however, it is perceived that the cost andcomplexity of such systems that is portable enough to be carried all thetime by a pedestrian are probably too high. Other technologies thatwould potentially allow AL of all objects (forktrucks and pedestrians)do exist, and will be discussed below. Instead, for example, an ALsystem like that disclosed for forktrucks alone may be used, because theforktrucks typically have the necessary size and access to power toallow practical AL to be performed. That AL information will be providedto the central processor which will be capable of tracking the movementof forktrucks through the facility with the demonstrated mapping offacility structure (walls, racking, etc.). Where this example differsfrom existing systems is in how the AL information in the centralprocessor is used to determine dangerous situations and provide moreeffective, and preferably, more personalized warnings of those dangers.For example, FIG. 7 illustrates a forktruck F moving between two rows ofracking R toward a double-blind (blind in both lateral directions)intersection 70 with pathway P. Rather than use the central processor toilluminate a beacon at the intersection and provide a generalizedwarning that might be easily missed or ignored, an alternative is tohave the central processor formulate a threat- and/or location-specificwarning based on the specific hazard to be conveyed to affectedpedestrians (e.g. those within the potential danger area). Potentiallyaffected pedestrians would have the ability to receive thethreat-specific warnings. For example, if the aisle the forktruck ismoving down is designated as aisle 6, given the AL and tracking abilityof the central processor, it is capable of formulating a warning such as“Forktruck approaching intersection from aisle 6, heading north—usecaution” to be conveyed to pedestrians approaching that blindintersection from either direction along pathway P. That message wouldthen be conveyed to some means for communicating that message to thepotentially affected pedestrians.

It may be desirable for this message to only be conveyed to pedestriansthat could actually be harmed by the forktruck approaching thatintersection. There are different methods or ways to achieve that end.One category of such approaches would be “passive” communicationsystems, in which the threat-specific warning is conveyed irrespectiveof whether endangered pedestrians have been detected in some manner. Forexample, the warning could be broadcast by conventional RF transmitters72 a, b illustratively positioned on the ends of the racking R adjacentintersection 70, and any RF receivers within a given range could detectthe signal. Illustratively, the field shape or range of thattransmission could be modulated based on the nature of the threat toselectively warn pedestrians in a certain proximity or direction fromthe threat. The central processor could use AL position and heading datato determine the size of the area adjacent, for example, aisle 6intersection within which pedestrians could be harmed if the forktruckcontinues its then-current trajectory (referred to in this context asthe “danger zone”). The size of that area would presumably get smalleras the forktruck F got closer to the intersection 70. In addition to thewarning message itself, the central processor could also provide the RFtransmitter with the information about the size and shape of the dangerzone. The transmitted warning signal would not only convey the message,but would only be broadcast to be received with adequate signal strengthby only those receivers in the danger zone. Such an arrangement mayplace an RF transmitter at or adjacent the “danger zone” in questionwhich could be addressed by the central processor.

Another way to transmit a generalized, but location-specific warning isto use directional sound. For example, ultra-sound can be used to createfocused beams of wave energy from a reasonably-sized source such as, forexample, the size of a conventional speaker. The focused beam maintainsits integrity for long distances, such that only those individuals inthe path of the beam receive the waves. As the ultra-sonic frequencywaves propagate, they interact with each other and the surrounding airin predictable ways. Thus, an audio input signal can be converted intoan ultrasonic directional sound beam that will interact with itself andthe air to result in the listener hearing a reproduction of the originalaudio signal. Given the ability to collimate and focus this sound, itcan be directed at very specific physical areas, for example, an areawhere one would want to warn a pedestrian of an attendant danger.Returning to the example of FIG. 7, directional sound generators aremounted at 72 a and 72 b and are aimed at potentially dangerous areasbased on the approach of the forktruck F to the intersection 70, and thecentral processor would formulate appropriate warnings based on the ALposition of approaching vehicles. Modulation of the shape and size ofthe directional sound warning could be provided based on vehicle speedand position (e.g. the warning area getting smaller as the vehicleapproaches).

In an “active” communication system, warnings (general orendangered-pedestrian specific) are generated only when there is thepotential for danger based not only on forktruck approach or presence,but also the sensed presence of a threatened individual. Some means fordetecting the presence of such an individual will be required in such asystem. Some example systems employ motion or presence sensors such as,for example, the I-Zone sensor used by Rite-Hite Doors, Inc. ofMilwaukee, Wis. to detect the presence of moving objects adjacent aclosing high-speed door. A semi-cylindrical lens with alternating maskedand unmasked sections divides the field of view of a passive IR sensorinto spaced fan-shaped detection areas. According to the logic, an IRsignal has to be detected by consecutive detection areas within a giventimeframe to trigger a detection event of a moving object. Other formsof presence/motion detection can be employed. Such a sensor is installedat the potentially hazardous intersection 70 of FIG. 7 (although this isonly an illustrative example). An approaching forktruck (as determinedby the AL central processor) makes the sensor “hot”. In some examples,the sensor may continuously sense an area and send output signals, andthe output signals may be ignored until the area is hot. In otherexamples, the sensor is only powered when the area is “hot” or adangerous condition is sensed. Either way, the potentially dangerousapproach of a forktruck to the monitored area makes it “hot” for thedetection of people. Such a detection event can trigger a generalizedwarning, or a threatened-pedestrian specific warning assuming that anadequate communication channel exists to allow for such. Safety could beenhanced by also communicating the detection of the person in the hotzone back to the forktruck driver or even imposing speed governance onthe vehicle in such a situation.

Relatedly, other technology could be used to determine if there arepedestrians in the danger zone (e.g. RFID radar, triangulation withRFID, actual or localized GPS, or ultra-wideband UWB detection). Asabove, such detection systems could continuously monitor a dangerousintersection (e.g., the intersection 70 of FIG. 7), and the outputsignal could be ignored until a centralized AL system detects anapproaching forktruck F. Alternatively, the centralized AL system couldactivate or make “hot” such detection systems only when the forktruck Fapproaches intersection 70 and a potentially dangerous situation isdetected. Once endangered pedestrians are detected, threat-specificwarnings are sent to them. If a system is used (e.g., RFID) that alsoallows identification of the pedestrian, a truly personal warning (e.g.,Tom, a forktruck is approaching) could be conveyed.

In other examples, instead of use of an AL system to identify that theforktruck F is approaching the intersection 70, other systems could beused such as a photoeye/reflector described above. Detection of theapproach of a forktruck could activate or make “hot” a system fordetecting people in the danger area. Thus, a comprehensive system forcomprehensively monitoring (e.g., every square inch) of a facility maynot be required. Rather, it may be possible to identify high-risk area,like intersection 70, and invest in a relatively more sophisticated,robust detection/sensing systems for that location to work inconjunction with lower level sensing to achieve enhanced safety. Indeed,an industrial facility may be implemented with a patchwork of theexample sensing/detecting regimes described herein, along withassociated communication channels and techniques. In this manner,choices can be made about the appropriate sensing and communication ingiven areas given the perceived risks of danger in the various areas.Thus, a system can be implemented that is tailored for different partsof a facility that have different levels of risk (e.g., blindintersections and doorways opening into forktruck aisle ways beingparticularly dangerous, while open floor space being generally less so).Employing different sensing/communication regimes (some more of whichwill be described below), an optimized system can be implemented wherethe appropriate regime is selected and implemented based on theperceived risk of danger in different areas of the facility.

Different examples of systems based on AL of forktrucks have beendescribed herein, for example using the previously-mentioned machinevision system. The first example was “passive” in that general warningswere given in potentially dangerous areas being approached by a vehiclewithout regard for whether or not an individual was there. The nextlevel was an “active” system for determining the presence of anindividual in a potentially dangerous area, and providing warning onlyin that situation. Sensing can employ presence/motion sensing devices orAL devices that may also facilitate the formulation and delivery ofeffective, personal warnings. In other examples, described below, allobjects are located and/or tracked.

As with the proximity-based and more limited absolute location systemsdescribed above, different types of instruments or technologies areavailable for location and tracking the entities of interest (e.g.,forktrucks and pedestrians). Such example systems have already beendescribed relative to forktrucks, and the machine vision technology usedin such systems can be configured or adapted to pedestrians as well. Inthat context, however, it might be optimal to reverse the location ofthe location markers (bar codes, etc.) and the cameras viewing them sothat the bar codes move with the tracked entities, and the cameras arefixedly mounted in the ceiling. This prevents the need for eachpedestrian to have to carry the weight and associated electronics andpower source of both a camera and networking components. However, lineof sight issues with bar codes on people could limit this approach.Other camera or optically-based systems for locating and trackingpeople, however, could be adapted for this application. For example,camera and image-processing technologies exist for the purpose oflocating and tracking shoppers in retail settings—to determine whatkinds of displays they might be attracted to, and to study shopping anddwell time patterns. Generally these systems employ image processing toraw video images to look for image patterns associated with people. Animage pattern for a given individual is then tracked as it movesthroughout the space. Algorithms can then be applied to the image datato extract useful information about movement patterns and dwell times atparticular locations. Such systems can then correlate locations tospecific product displays to provide useful marketing feedback andinformation. Other uses of this technology include security andpatient-monitoring applications. Such systems can have a very high levelof sophistication, but this can come at the expense of relatively largeprocessing power and time requirements, as well as relatively highcosts. A benefit, however, is that the entities of interest do not needto be equipped with any special equipment to allow them to be locatedand tracked.

Other technologies exist and are emerging in the automotive context thatcould have application here. These technologies are primarily directedat avoiding collisions between vehicles (particularly when one is in theblind spot of the other), but are expanding in to broader applicationsof providing warning or taking corrective action for obstructions and/orpedestrians. A given vehicle may be equipped with a host of differenttechnologies to serve these various purposes.

Other systems applicable to the examples disclosed herein require someform of equipment or tag to be carried by the entities of interest, butcan provide location and tracking with high fidelity. RFID systems areone example. There, entities of interest are each provided with areadable RFID tag, preferably with a unique identifier. An array ofreaders can be provided in the facility, which periodically orinterrogate the tags. Location can be determined by triangulation, orother techniques known to those of skill in the art including RFID radartechniques. For the tracking of people, use of this and relatedtechnology is employed for the tracking of patients in medicalfacilities. In that context, we have seen different technologies applieddepending upon whether the tracking of individuals is done inside oroutside of the building. Choices also need to be made about whether touse passive or active tags, as power requirements on tracked entitiescan be different based on that choice. The location and tracking datacollected from such a system is monitored to ensure that patients stayin authorized areas and do not wander beyond them. Warning signaling ofsuch a situation can either be provided to a system operator or to theindividual themselves if they are capable of taking corrective action ontheir own. Application of this technology to track shopping carts in aretail grocery using techniques of RFID radar to actively locate andtrack up to hundreds of carts real-time has also been demonstrated

Another example system employs technology that is similar, but that isadvertised as not being subject to the limited range applications ofRFID is ultra-wideband (UWB) technology. Here, tracked entities ofinterest also carry tags like in the RFID setting. An array of UWBinterrogators are distributed throughout the facility and use a varietyof techniques (e.g. triangulation, Doppler processing, etc.) to locateand track entities based on the response of the tags to interrogationsignals. Examples of use of UWB technology includes social networkingsettings, in which the central processor not only locates and tracks allof the individuals, but also performs processing on storedcharacteristics for each individual so as to identify when twoindividuals in close proximity share a common interest. A communicationchannel from the central processor informs one or both individuals ofthe match in interests to allow them the opportunity to have a directinteraction. Some examples provide the information to an individual in a“heads-up” display embedded in their glasses.

As mentioned above, the great flexibility and optimization of thesevarious sensing and/or locating and tracking technologies can bebeneficially implemented in that the optimal technology can be selectedfor a given application. Different parts of a facility may represent alower risk of an accident, and can thus be monitored by a lower level(and likely lower-priced) technology option. Similarly, a giventechnology may be better suited to the sensing or locating/tracking of agiven entity (e.g. a forktruck or a person). If that is the case,separate technologies could be used for monitoring the location offorktrucks versus people. It may also be possible to use level oftechnology for “gross” location (e.g. RFID) and to then switch toanother technology (e.g. based on line of sight) for “finer” location(e.g. when the entities are less than ten feet apart). Given theserealities, and the desirability of being able to provide the mosteffective and reliable safety system for the best price, an aspect ofthis disclosure is the identification of appropriatesensing/locating/tracking technologies, combined with an applicationknowledge of the types and nature of hazards at different parts of afacility to create an integrated system of perhaps one, but likelyseveral such technologies that provides a cost-effective way to achievethe desired safety goals.

The example systems described herein may be employed withsensing/locating/tracking to provide enhanced industrial safety systemsIn addition, the data generated by the example systems regarding theentities of interest may be analyzed to determine the possibility ofhazards and to allow the formulation of appropriate responsive action(e.g., in the form of warnings). For the purposes of this description,this analysis of the data regarding the entities of interest will bereferred to as “hazard discrimination” and performed by what we term a“hazard discriminator”.

Some of the example systems described above employ a low level or simpleform of hazard discrimination. In the example system employingproximity-based sensing systems, hazard discrimination came in the formof detection of signal strength above a certain threshold. In the caseof the forktrucks sending out RF signals being detected by receiverscarried by individuals, the detection of that above-threshold signalstrength served as hazard discrimination in that the threshold wasselected such that detection was indicative of a potentially dangerousproximity of the transmitting forktruck. In that case, hazarddiscrimination was distributed and performed locally by thepotentially-endangered entity—in this case the pedestrian. This type ofdistributed hazard discrimination could also place the hazarddiscrimination on the forktruck. In the example described above inconnection with FIG. 5, a forktruck included a directional antennaarray, which gave input to a GUI which depicted the locations ofpedestrians relative to the forktruck (FIG. 5). With just the GUI, thejudgment of the forktruck operator would represent the hazarddiscriminator, but the processor needed to generate the display couldalso perform hazard discrimination. In that case, for example, theprocessor detects when a sensed pedestrian is within proximity of theforktruck considered as dangerous. Note that hazard discrimination inthis context is not limited to forktruck/pedestrian interactions, butcould apply to forktruck to forktruck interactions, or forktruck tofixed object. The discriminator could be programmed to apply differentthresholds for different threats. For example, the distance thresholdfor identifying the proximity of another forktruck as being dangerous issmaller than the threshold for a pedestrian, since the approachingforktruck has the ability to move faster than a pedestrian. Preferably,the hazard discriminator would have the flexibility to be programmedwith different operations for different situations in this manner.Another example of the forktruck performing hazard discrimination wouldbe a case where pedestrians are wearing RFID tags and the forktruck isequipped with a reader and an ability to determine, for example, thetime delay between sending of an interrogation signal and receipt ofresponse to give an indication of the location of the pedestrian. A timedelay below a threshold is considered by the hazard discriminator to beindicative of a pedestrian in dangerous proximity to the forktruck.Other hazard discrimination operations could be applied.

Hazard discrimination based on proximity is not, however, limited to adistributed basis. Proximity could be the relevant metric for acentralized hazard discriminator using as input detailedlocation/tracking data about all entities of interest. Again, dependingon the application, that data may be provided by differentsensing/locating/tracking technologies for different entities ofinterest. Even so, the centralized discriminator could be programmed touse a proximity hazard discriminator or operation to discriminatehazards. For example, the centralized discriminator may access afacility layout database and can be configured to calculate the distancebetween different entities of interest to determine when proximitybetween entities of interest is indicative of a potential hazard. Again,interactions between different entities of interest(forktruck/pedestrian v. forktruck/forktruck) may require differentthresholds or operations for determining the existence of a potentiallydangerous situation. Moreover, whether proximity-based hazarddiscrimination is performed on a distributed or centralized basis, itmay be desirable to establish multiple thresholds for specificinteractions of entities. For example, in the case of an interactionbetween a forktruck and a pedestrian, the hazard discriminator may beprogrammed to consider a first proximity as potentially dangerous andrequiring continued attention by the discriminator—but not yet rising tothe level where any corrective action (e.g. warning signaling) isindicated. If subsequent analysis (within some meaningful timeframe) ofthe proximity of the entities indicates that they are even closer, andbelow a second predetermined threshold, the discriminator may beprogrammed to consider that proximity as a relatively higher potentialdanger, and thus initiate a first level of warning signal (the term“initiate” is used broadly here, as the discriminator itself may notgenerate the actual warning signal, but could provide an output orsignal level when that level of threat is detected, which signal couldbe used by another component or sub-system to actually formulate anddeliver the warning). Finally, if the entities continue to draw closerin a temporally meaningful period, as indicated by subsequent analysisof proximity data, the discriminator could be programmed to determinethis proximity as falling below a third threshold, and be indicative ofan imminent collision. Such a determination would then initiate ortrigger an even higher level of corrective action such as providing amore forceful or discernable warning, or applying the brakes ordisabling the engine of the forktruck to prevent its further movement.The benefits of such a phased approach to hazard discrimination andwarning include the reduction of nuisance warnings, pedestrians andforktruck operators get notification-level warning when the threat islow, and immediate-attention-required level warning when danger isreally imminent—in the hopes that they will pay attention and respond tothe latter, while having at least their awareness raised by the former.Indeed, in the scenario just described, some level of potentiallydangerous proximity as determined by the hazard discriminator does noteven result in any warnings, so long as the threat of potential dangerdoes not increase when the data is analyzed at a later time.

In some examples, hazard discrimination based on proximity alone may nottake into account the physical realities of a situation or danger suchas the presence of structure (building walls, columns, storage racking)that would effectively prevent a collision between a forktruck andpedestrian that are otherwise in dangerously close proximity. In someexamples, different techniques are applied to remedy this weakness,depending on the sensing technology employed. For an application where aforktruck is transmitting RF to be detected based on signal strength bydetectors carried by pedestrians, an RF shielding can be added to thefixed obstacles or structure so that the RF would not be transmittedthrough those obstacles. In the case of a forktruck carrying an RFID orUWB reader and sending interrogation signals to tags carried bypedestrians, the fixed obstacles could be provided with tags assigned toID's that the readers are programmed to recognize as obstacles that thehazard discriminator should take into account when determining theexistence of a threat. Other direct techniques can be used incentralized locating/tracking hazard discrimination regimes. In thatcontext, the hazard discriminator can be programmed with a mapping ofthe location of the fixed obstacles throughout the facility. The hazarddiscriminator could then include a step of determining whether such anobstacle is present between two entities of interest.

A flowchart representative of machine readable instructions that may beexecuted to implement an example system described herein is shown inFIG. 8.

The example machine readable instructions of FIG. 8 begin execution atblock 80 at which location data for the two entities of interest (e.g. aforktruck and a pedestrian) is received as inputs. For example, sensorsand/or detection devices may be communicatively coupled to a processor,which receives signals from the sensors at block 80. Based on thereceived signals, the hazard discriminator determines whether theentities are in dangerous proximity (block 90). If the hazarddiscriminator determines that the location of the entities of interestsare not in dangerous proximity, control returns to block 80 to await thenext data input (e.g., from the sensors). If the hazard discriminatordetermines that the location of the entities of interest are indangerous proximity (block 90), control advances to block 100, in whichlocations of fixed obstacles are identified via, for example, byreference to a look-up table (e.g., data retrieved via a data storagedevice). At block 110, the location data of the entities of interest iscompared to that of the fixed obstacles to determine whether a fixedobstacle is present between the entities of interest. If the hazarddiscriminator determines that a fixed obstacle is present between theentities of interest (block 110), the hazard discriminator determinesthat a potentially dangerous condition does not exist and controlreturns to block 80. If the hazard discriminator determines that a fixedobstacle is not present between the entities of interest (block 110), adanger condition is indicated, and control initiates a warning (block120). Control then returns to block 80.

In addition to providing this type of enhancement to proximity-baseddetection, a central locating/tracking system can provide other benefitsthat a distributed proximity-based system cannot (e.g. one based onsignal strength detection alone). For example, the processing capabilityneeded for tracking over time, allows the hazard discriminator in such asystem to include an aspect of predictive analysis within its operation.An example of this predictive ability is illustrated in FIG. 9A. There,a first data point of a forktruck F and a pedestrian P are representedby open circles. The second data points (taken later at somepredetermined interval) are represented by closed circles. Note that theseparation between the data points for the forktruck is further spacedthan that for the pedestrian indicating the forktruck moving at a fasterspeed. In this example, the hazard discriminator is capable ofdetermining both the speed and direction of both entities andcalculating a trajectory vector V for each entity. The hazarddiscriminator compares the two trajectory vectors V (sub-designated “p”for pedestrian and “f” for forktruck to ascertain whether continuedmovement on that vector would result in a collision, and, if so,initiate corrective action. Realistically, however, movement of suchentities rarely continues on the same vector for an extended time.Accordingly, an improvement to pure vector analysis will be referred toherein as trajectory vector expansion which enhances the predictivevalue of vectorial analysis. Under this technique, the trajectory vectorof each entity is expanded according to a predetermined expansionfactor. The expansion factor can be calculated based on a variety offactors, such as speed range of the entity (large for forktrucks, smallfor pedestrians), acceleration capability of the entity (again large forforktrucks, small for pedestrians), the agility of the entity (smallerfor forktruck, larger for pedestrians if defined as the ability tochange direction with a relatively smaller linear displacement), andpossibly other factors. According to the technique, whenever atrajectory vector V is calculated for a given entity, the expansionfactor is then mathematically applied to result in an expandedtrajectory vector E, as depicted in FIG. 9B, and sub-designated “vp” forvector-pedestrian and “vf” for vector-forktruck. Comparison of the twofigures demonstrates the potential value of this type of analysis.According to the unrefined operation of FIG. 9A, the vectors do notintersect, and a potentially dangerous situation would thus not beindicated. In the example of FIG. 9B, however, the expansion of thetrajectory vectors results in overlap 130, which could be interpreted bythe discriminator as indicative of a potentially dangerous situation. Inthe current example, the trajectory vectors V are expanded. Rather thanapplying an expansion factor to the vectors, for example, the unexpandedvectors could be analyzed. Rather than requiring overlap of the vectors,a dangerous condition could be indicated by a proximity of the vectorswithin a given range (e.g., the condition indicative of a hazard isexpanded, rather than the trajectory vectors themselves). In thisexample, the proximity indicative of a dangerous condition ispredetermined based on a variety of factors such as entity speed range,acceleration, agility, etc.

FIG. 9C is a flow diagram illustrating example machine readableinstructions 9000 which may be executed to implement a system thatincludes predictive analysis such as that illustrated in FIGS. 9A and9B. The system is provided with appropriate sensors to detect thepresence and movement characteristics of objects and people as explainedabove. It is also provided with a processor platform to receive the datacollected by the sensors and to execute the instructions of FIG. 9C toidentify threats of collision and transmit corresponding warningsystems. For ease of explanation, the flowchart of FIG. 9C does notaddress data collection, but rather focuses on the detection ofcollision threats and transmission of corresponding warning signals.However, it is to be understood that data representing current positionsand/or movement characteristics is constantly or substantiallyconstantly being collected by the system and processed in accordancewith the flowchart of FIG. 9C. Therefore, it is also to be understoodthat the system will instantiate multiple versions of the instructionsrepresented by FIG. 9C (e.g., multiple threads each operating oncorresponding sets (e.g., pairs) of objects in sufficient proximity tomerit comparison) executing in parallel to quickly identify threats andissue warning signals in a time useful to preventing collisions. To thisend, the system analyzes objects using an initial proximity test toidentify sets of movable objects within a distance of interest (e.g., 50feet) and with no barrier (e.g., a wall) therebetween to identify setsof objects to be analyzed. An instance of FIG. 9C is then spawned foreach identified set of objects. Each instance may persist (and, thus,continuously monitor and analyze the objects in its set) until there areinsufficient active (e.g., moving) objects in the corresponding set tomake collision a possibility, or may terminate upon analyzing all objectcombinations in its set one time and issuing any necessary warnings.This process of identifying sets of objects and spawning new instancesof FIG. 9C is repeatedly executed to ensure threats of collision aretimely identified. The process of spawning new instances of threads maybe initiated on a time basis, an event basis, or be run continuously.The frequency with which the process is executed will depend on whetherthe instances of FIG. 9C are meant to persist or to terminate after afinite number of executions (e.g., one). An example manner ofimplementing a system to spawn instances of FIG. 9C is shown anddescribed above in connection with FIG. 8. However, if FIG. 8 is adaptedto this function, block 120 of FIG. 8 is to be replaced withinstructions to generate a set of objects in dangerous proximity and tospawn an instance of FIG. 9C to analyze the same.

Focusing now on one instance of FIG. 9C, at block 902, if two or moreentities of interest are sensed to be in proximity of each other, thesystem samples movement of each entity in the set of objects (e.g.,persons, vehicles, etc.) under analysis at least two periods or pointsin time. For example, the system receives first data points for each ofthe entity of interest and second data points for each of the entity ofinterest at a predetermined interval of time from the first data points(block 902). The movement of a corresponding entity may be based on, forexample, the speed and/or direction of the respective entity. The systemthen generates a trajectory for each entity in the set based on themovement sample determined by the system (block 904). At block 906, thesystem expands each entity's trajectory based on at least onecharacteristic of movement of that entity. For example, the systemapplies an expansion factor to determine an expanded trajectory vectorfor each entity of interest (block 906). The expansion factor can becalculated, for example, based on a variety of factors, such as speedrange of the entity (large for forktrucks, small for pedestrians),acceleration capability of the entity, the agility of the entity, etc.At block 908, each entity's expanded trajectory vector is then analyzedfor overlap with the expanded trajectory vector of the other entities inthe set to assess the possibility for a collision. If an overlap betweenany two modified safety zones is detected (block 910), a warning signalis transmitted to the entities with the overlapping safety zones (block912). If there is no overlap (block 910), then no warning signal isgenerated.

The instance of FIG. 9C next determines whether any entities are to beremoved from its set of objects (e.g., has an entity left the room,moved behind a wall, moved outside of the threshold distance from allother objects, etc.) or added to its set of objects (e.g., has an objectentered the room, moved from behind a wall, etc.) (block 914). If so,the set is modified (block 916). If no modifications to the set arewarranted (block 914) or after the set has been modified (block 916),the system determines if the present instance (e.g., thread) of FIG. 9Cis to persist (e.g., more than one object remains in the set so thatcollisions are still a possibility) (block 918). If it is to persist,control returns to block 902. Otherwise, this instance of FIG. 9C isterminated.

An alternative example for using a centralized location/tracking regimefor entities of interest uses a hazard discrimination techniqueinvolving an analysis similar to Venn diagrams to determine potentiallydangerous situations. In this example, the central processor drawsfigures around entities of interest indicative of a safety zone aroundthe entity. While the simplest safety zone figure for such use is acircle, other safety zone figures that take factors into account aboutthe entity are also possible. For example, the determined direction ofmovement of an entity of interest could alter the shape of the safetyzone figure. As shown in FIG. 10A, the pedestrian entity P is moving tothe right in the figure. Accordingly, the safety zone figure for thatentity of interest is calculated as being biased in that direction, forexample, as an oblong shape with greater area in front of rather thanbehind pedestrian P. The size and shape of the safety zone figure ismodified based on the recent movement history of the entity. In otherexamples, the size and/or shape are modified based on other informationsuch as the level of training or experience of the given entity ofinterest (such information being stored, for example in a lookup tableaccessible to the processor). In that case, an individual with highertraining might have a relatively smaller safety zone figure since hisincreased safety awareness from the training might reduce the area inwhich other entities might represent a threat to him. Similarmodification of the size and shape of the safety zone figure could alsobe carried out for forktruck or other vehicular entities, with, forexample, the average speed of the vehicle over time. For a “fast”forktruck driver, the safety zone figure is relatively larger, since hishigher speed represents potential danger in a greater area. Hazarddiscrimination is carried out by the processor by calculating andupdating safety zone figures for all entities of interest. A hazarddiscriminator then dynamically seeks overlaps of the safety zone figures(such as the safe zone figure 140 in FIG. 10A) to determine potentialhazards. This is analogous to Venn diagrams where overlapping regions oftwo-dimensional safety zone figures representative of set spaces isindicative of common set members for the spaces represented by thesafety zone figures. The hazard discriminator could look simply for anyoverlap between the safety zone figures of all entities, and initiatecorrective action when overlap is found. However, in other examples, asoverlap is first found, the system (e.g., via a processor) monitors thedevelopment of the size and shape of the overlap of the safety zonefigures for these two entities. Presumably, as the entities draw closer,the overlap would increase. The processor could be programmed toinitiate higher levels of warning based on a determination of anincrease in the size, or change in the shape of the overlap indicativeof greater danger. A similar technique could be used for taking fixedobstacles (walls, racking, etc.) into account. In that scenario, theprocessor is programmed with the coordinates of such obstacles, sincethe presence of an obstacle between two entities may reflect a situationwhere they cannot collide on their current trajectories based on thepresence of the obstacle. In such examples, the processor is programmedto ignore an overlap in the safety zone figures of two entities ofinterest. This is done, for example, by ignoring an overlap for aninterposed obstacle, and/or by dynamically modifying the shape of thesafety zone figures for the entities to take into account theirproximity to a fixed obstacle, insomuch as the presence of that obstacleimpacts the possible path trajectories for that entity.

The safety zone figure technique could also combine both actual overlapof figures with their relative proximity. For example, a close proximityof figures without overlap could trigger the processor to monitor thoseentities for a reduction of that proximity, up to and including theiractual overlap. Potentially, the processor could be programmed toinitiate corrective action (warning, signaling, etc.) based only on suchproximity of figures instead of waiting for the threat to rise to thepoint where the figures actually overlap. The processor similarly couldbe programmed with determinative operation based on past movementpatterns of the entities to predict likely movement paths and modify thesafety zone figures accordingly. Potentially, such analysis could alsolead to the processor initiating corrective action before a potentiallyhazardous situation actually occurs—perhaps resulting in low-levelwarning being initiated to raise the awareness of the entities topotential danger based on their current position, and the likely path ofsuch entities based on history.

FIG. 10B is a flow diagram illustrating example machine readableinstructions 1000 which may be executed to implement a system such asthat illustrated in FIGS. 2A, 2B, 3A, 3B, 4A, 4B and/or 10A. FIG. 10C isanother example flow diagram illustrating example machine readableinstructions 1020 which may be executed to implement a system such asthat illustrated in FIG. 10A. The systems implemented by the machinereadable instructions illustrated in FIGS. 10B and 10C may be used withthe example systems described above in connection with FIGS. 6C, 8and/or 9C.

The systems implemented by the machine readable instructions illustratedin FIGS. 6C, 8, 9C, 10B and 10C are provided with appropriate sensors todetect the presence and movement characteristics of objects and peopleas explained above. They are also provided with a processor platform toreceive the data collected by the sensors and to execute theinstructions of, for example, FIGS. 10B and 10C to identify threats ofcollision and/or transmit corresponding warning signals. For ease ofexplanation, the flowcharts of FIGS. 6C, 8, 9C, 10B and 10C do notaddress data collection, but rather focuses on the detection ofcollision threats and/or transmission of corresponding warning signals.However, it is to be understood that data representing current positionsand/or movement characteristics is constantly or substantiallyconstantly being collected by the system and processed in accordancewith the flowcharts of FIGS. 6C, 8, 9C, 10B and/or 10C. It is also to beunderstood that the systems will instantiate multiple versions of theinstructions represented by FIGS. 6C, 8, 9C, 10B and/or 10C (e.g.,multiple threads each operating on corresponding sets (e.g., pairs) ofobjects in sufficient proximity to merit comparison) executing inparallel to quickly identify threats and issue warning signals in a timeuseful to preventing collisions. To this end, the systems analyzeobjects using an initial proximity test to identify sets of movableobjects within a distance of interest (e.g., 50 feet) and with nobarrier (e.g., a wall) therebetween to identify sets of objects to beanalyzed. An instance of FIGS. 6C, 8, 9C, 10B and/or 10C is then spawnedfor each identified set of objects. Each instance may persist (and,thus, continuously monitor and analyze the objects in its set) untilthere is insufficient active (e.g., moving) objects in the correspondingset to make collision a possibility, or may terminate upon analyzing allobject combinations in its set one time and issuing any necessarywarnings. This process of identifying sets of objects and spawning newinstances of FIGS. 6C, 8, 9C, 10B and/or 10C are repeatedly executed toensure threats of collision are timely identified. The process ofspawning new instances of threads may be initiated on a time basis, anevent basis, or be run continuously. The frequency with which theprocess is executed will depend on whether the instances of FIGS. 6C, 8,9C, 10B and/or 10C are meant to persist or to terminate after a finitenumber of executions (e.g., one). An example manner of implementing asystem to spawn instances of FIGS. 10B and/or 10C is shown and describedabove in connection with FIG. 8. However, if FIG. 8 is adapted to thisfunction, block 120 of FIG. 8 is to be replaced with instructions togenerate a set of objects in dangerous proximity and to spawn aninstance of FIG. 10B or 10C to analyze the same.

Focusing now on one instance of FIG. 10B, at block 1002, the systemcreates a safety zone surrounding at least one entity in the set ofobjects (e.g., one or more person(s), one or more vehicle(s), etc) underanalysis. The size and/or shape of the safety zone is then modifiedbased on one or more characteristic(s) of movement of the at least oneentity such as, for example, the direction of travel of that entity(block 1004). For example, the system may modify the safety zone basedon one or more of the direction of travel of the entity (e.g., as shownin FIGS. 2A and 2B), the speed of the entity (e.g., as shown in FIGS. 3Aand 3B), the direction of movement of the entity (e.g., as shown inFIGS. 4A and 4B) and/or any other characteristic(s) of movement of theentity of interest. At block 1006, the entity's modified safety zone isthen analyzed. A warning signal is transmitted or generated to alert orprovide a warning to other entities within the modified safety zone ofthe presence or proximity of that entity based on the modified safetyzone (block 1008). If there is no other entity within the modifiedsafety zone, then no warning is generated (e.g., received by a receivercarried by a pedestrian). The system determines if the present instance(e.g., thread) of FIG. 10B is to persist (block 1010). If it is topersist, control returns to block 1002. Otherwise, this instance of FIG.10B is terminated.

Focusing now on one instance of FIG. 10C, at block 1022, the systemcreates a safety zone surrounding each entity in the set of objects(e.g., one or more person(s), one or more vehicle(s), etc) underanalysis. The system then modifies the safety zone of each entity basedon one or more characteristic(s) of movement of that respective entity(block 1024). For example, the size and/or shape of each entity's safetyzone may be modified based on a first characteristic of movement of thecorresponding entity such as, for example, the speed of the respectiveentity. Additionally or alternatively, the size of each safety zone maybe modified based on a second characteristic of movement of thecorresponding entity such as, for example, the direction of travel ofthe respective entity. Additionally or alternatively, the safety zonemay be modified based on a third characteristic of movement such as, forexample, a position of a vehicle steering and/or any othercharacteristic(s) of movement of an entity of interest. Each entity'smodified safety zone is then analyzed for overlap with the modifiedsafety zone of the other entities in the set to assess the possibilityfor a collision (block 1028). If an overlap between any two modifiedsafety zones is detected (block 1028), a warning signal is transmittedto the entities with the overlapping safety zones (block 1030). If thereis no overlap (block 1028), then no warning signal is generated.

The instance of FIG. 10C next determines whether any entities are to beremoved from its set of objects (e.g., has an entity left the room,moved behind a wall, moved outside of the threshold distance from allother objects, etc.) or added to its set of objects (e.g., has an objectentered the room, moved from behind a wall, etc.) (block 1032). If so,the set is modified (block 1034). If no modifications to the set arewarranted (block 1032) or after the set has been modified (block 1034),the system determines if the present instance (e.g., thread) of FIG. 10Cis to persist (e.g., more than one object remains in the set so thatcollisions are still a possibility) (block 1036). If it is to persist,control returns to block 1022. Otherwise, this instance of FIG. 10C isterminated.

In the examples of FIGS. 6C, 8, 9C, 10B and 10C the machine readableinstructions comprise one or more programs for execution by a processorsuch as the processor 1712 shown in the example computer 1700 discussedbelow in connection with FIG. 17. The program may be embodied insoftware stored on a computer readable medium such as a CD-ROM, a floppydisk, a hard drive, a digital versatile disk (DVD), or a memoryassociated with the processor 1712, but the entire program and/or partsthereof could alternatively be executed by a device other than theprocessor 1712 and/or embodied in firmware or dedicated hardware.Further, although the example program is described with reference to theflowcharts illustrated in FIGS. 6C, 8, 9C, 10B and 10C, many othermethods of implementing the example system disclosed herein mayalternatively be used. For example, the order of execution of the blocksmay be changed, and/or some of the blocks described may be changed,eliminated, or combined.

As mentioned above, the example processes of FIGS. 6C, 8, 9C, 10B and10C may be implemented using coded instructions (e.g., computer readableinstructions) stored on a tangible computer readable medium such as ahard disk drive, a flash memory, a read-only memory (ROM), a compactdisk (CD), a digital versatile disk (DVD), a cache, a random-accessmemory (RAM) and/or any other storage media in which information isstored for any duration (e.g., for extended time periods, permanently,brief instances, for temporarily buffering, and/or for caching of theinformation). As used herein, the term tangible computer readable mediumis expressly defined to include any type of computer readable storageand to exclude propagating signals. Additionally or alternatively, theexample processes of FIGS. 6C, 8, 9C, 10B and/or 10C may be implementedusing coded instructions (e.g., computer readable instructions) storedon a non-transitory computer readable medium such as a hard disk drive,a flash memory, a read-only memory, a compact disk, a digital versatiledisk, a cache, a random-access memory and/or any other storage media inwhich information is stored for any duration (e.g., for extended timeperiods, permanently, brief instances, for temporarily buffering, and/orfor caching of the information). As used herein, the term non-transitorycomputer readable medium is expressly defined to include any type ofcomputer readable medium and to exclude propagating signals. For any ofthe hazard discrimination techniques described herein, determination ofa potentially hazardous situation may not result in initiation ofcorrective action in the form of direct warnings. Rather, the centralprocessor could be programmed to take other corrective action. In theexample depicted in FIG. 11, a pedestrian P is about to enter apotentially dangerous high-traffic area as he enters the loading dockarea LD. Assuming that the processor has some means of directly orindirectly controlling an actuable barrier B, such as a safety gate ordoor, the processor can determine that entry of the pedestrian P intothe loading dock LD area is unsafe, and actuate the barrier in advanceof the pedestrian P entering the area. Actuation of the barrier wouldnot only physically prevent entry, but would also serve as a form ofwarning to the pedestrian. If coupled, for example, with a signalingapparatus (e.g., lights) closing of the barrier could also sensitize theforktruck drivers to the presence of a pedestrian. In an attempt toensure respect for the hazardous situation, the system could prevent thebarrier from opening until some form of acknowledgement of the danger bythe pedestrian. For example, he could be required to enter a securitycode, or to await receipt of an audible warning at the site before thegate opens. One could also envision a situation where the forktruckoperators are empowered with opening the barrier—but only after someform of acknowledgment of the danger, and then only opening the barrierwhen the condition is perceived by him to be safe, such as by a visualinspection of the area, or by direct verbal or other contact with theaffected pedestrian.

Communication of Threats

Having described a range of both sensing and hazard discriminationtechniques to enhance the quality of detection of potentialforktruck/pedestrian interactions (e.g. collisions), we turn now toenhancing safety in this environment by improvement of the communicationof hazards and/or information related to or empowering corrective actionto affected entities of interest. In addition to more effectivelydetecting hazards as disclosed above, achieving this goal may beenhanced by having a means of directing warning information and/orcorrective action information to an affected individual (and, perhaps,not to unaffected individuals) through a communication channel orchannels that have enhanced conspicuity relative to conventionalchannels or through more effective use of existing channels. It may alsobe achieved by providing a better quality of information to an affectedindividual, including specifics about the potential hazard that couldallow him to take corrective or avoidive action. These specifics couldinclude details about the threat itself, details about the location ordirection of the threat and/or temporal or imminence information aboutthe hazard. While a system achieving all of these goals is desired,safety could be enhanced by providing any of them, or sub-combinationsof the total. Throughout this portion of the description, it will beassumed that a sensing and hazard discrimination system exists and iscapable of interacting with the threat communication devices andtechniques described

Turning first to communication channels with enhanced conspicuity, aproblem with conventional warning systems (colored or flashing lights orstrobes, horns, buzzers, etc.) is that people tend to becomedesensitized to them because of their ubiquity. In addition, they aretypically area-general warnings, rather than being targeted to anindividual who is actually threatened. Because the warnings areeverywhere and generalized, they tend to become ignored over time.Moreover, relative to the aural channel, required hearing protectiondevices in some locations can severely limit the effectiveness of thischannel. Improvements to existing modes of communication enhance theirconspicuity.

Sound-based or aural communications of threats to an endangeredpedestrian (or other individual) are made more effective by allowing theendangered pedestrian himself to select the warnings or communication hewill receive. One example of this allows an individual to select theactual warnings he would receive by selecting the content for differenttracks on an MP3 player that he will carry with him and that will be thesource of his personalized warnings. One way of allowing for such apersonalized selection of warnings is for a pedestrian to actuallyrecord warnings of his choosing and in his own voice to provide warningsfor given situations. A list is provided to him of what tracks of theMP3 recording are played for different levels of dangerous situations(e.g. Track 1: approaching stationary forktruck; Track 2: forktruckapproaching at high speed, etc.), and the user could then recordwarnings that are relevant or attention-getting to him. In this manner,a user is able to select warning words or speech inflections that wouldget his attention. For example, a user may choose to include his ownname (perhaps shouted) in a warning track for an imminent danger, “JOHNSMITH—danger move NOW!” A colloquial analogy of this is how a parent cantypically more easily command their child's attention by using theirfirst, middle and last name. An endangered user should respond to urgentwarnings with the same level of attention. In other examples, anemployee's supervisor records the warning tracks—again with the ideabeing that a directive from a supervisor (even if recorded) might elicita more effective response than an unfamiliar voice making the warning.An alternative to recording full warning tracks for every situation isto record individual words or phrases, and then to provide the user withthe hardware and logic to be able to string these pieces together toform a relevant warning depending on the dangerous situationencountered. In an analogy to selecting one's ringtone on a mobilephone, a person could also be presented with a menu of canned orpre-recorded warnings, with the ability to select those that were themost attention-getting.

Another example for effectively conveying aural warnings or othercommunication uses negative sound, or silence. If potentially endangeredpedestrians have an MP3 player with recorded warnings, they could alsouse the MP3 player to listen to music. As a dangerous condition thatrequires the pedestrian to be warned is encountered, the first step ofthreat-communication may be to stop the music playing. Alternatively,instead of music playing when there are not warnings, a white-noisegenerator could also be provided with the white noise cessation at thetime of a warning being a means of attracting the user's attention. Asthere could be negative safety ramifications to pedestrians or others inan industrial facility listening to music or white noise, we are notrecommending such a practice, but present it as an example of a way toimprove on effectively capturing a user's attention when a warning needsto be conveyed to him.

Another example threat communication mode with improved conspicuitydisclosed herein is visual warnings. Rather than relying on wall orceiling-mounted lights for area-generalized warnings, conspicuity isenhanced in these examples by visually-based threat communication beingpersonalized to an individual who is threatened, or perhaps the sourceof the threat (a machine or an individual operating it). In the case ofa personalized visual threat-communication, safety glasses are providedwith an embedded source of light. A schematic view of an example pair ofsafety glasses 200 is shown in FIG. 12. Along the upper rims 210 of eacheyepiece, a longitudinally-extending light source 220 is provided, suchas a side-emitting fiber-optic cable. A source of light, such as amulti-color (for example, red and green) LED is carried elsewhere on theperson, along with control electronics and a power source, such as a 12Vbattery—all represented schematically in functional box 230. Some or allof the contents of functional box 230 could be carried on the glasses(e.g. the LED'S), on the wearer, or even elsewhere. Depending on whatcomponents are where and what accompanying electronics are present,either wired or wireless connections among components could be used. Thecontrols and glasses could be programmed to respond to various dangeroussituations (as detected by any of the sensing and hazard discriminationtechniques described above) by presenting light-signaling to the wearerof the glasses that is highly conspicuous by virtue of its proximity tothe eye of the wearer. Different colors or other modulations of thelight output from the fiber-optic cables 220 could be used to conveydifferent threats or levels of danger to the user. These will bediscussed in greater detail below. As an alternative to LED drivenfiber-optic cable, the longitudinally-extending light source could alsobe a small array of LEDs.

Although the power consumption in terms of creating the visual warningand powering the processor necessary for such a complex warning arehigh, “heads-up” displays could also be incorporated into safety glassesas such displays are currently incorporated into the goggles used bymilitary jet pilots. Such a heads-up display would actually projectwarning content in such as way so as to appear in front of the wearer.That warning content could be in the form of words, icons, symbols, etc.and could incorporate other features to enhance conspicuity such ascolors, changes in intensity, and the like.

Another example of enhanced-conspicuity visual threat communicationactually makes the potentially endangered pedestrian the source of thewarning signal. In this example, when a dangerous condition is detectedby a sensing and hazard discrimination system (such as a forktruckdriving dangerously close to a pedestrian), some part of the pedestrianis illuminated. In the representative drawing shown in FIG. 13, not onlydoes a light array 250 on the pedestrian's safety helmet H light up, butso do bracelets 260 on each of his arms. The intent is for thepedestrian to be a visual warning of the hazardous situation to thesource of the hazard—the forktruck and its operator through theillumination of the lights. But since the pedestrian probably cannot seethe light array on his helmet (unless perhaps the light signaling isalso tied to his safety glasses as described above), the lights on thebracelets 260 on his arms are intended to also convey the potentialdanger to him in a conspicuous way.

Enhanced visual conspicuity threat communication can also be carried bythe dangerous instrumentality—in this example a forktruck. The forktruckFT depicted in FIG. 14 includes a longitudinally-extending light source300 on some or the entire lower perimeter of the vehicle. Thelight-source might be LED driven side-emitting fiber-optic cable, anarray of LED's or any other suitable light source. Given that theselights are on a forktruck with access to a greater and more consistentpower source, conventional light sources could also be used. In anyevent, the light source 300 is capable of providing visual warning tosurrounding pedestrians by projecting light onto the floor surroundingthe forktruck FT, as shown at 310. Under normal operating circumstances(where the sensing and hazard discrimination system does not detect apotentially hazardous situation), the projected light could be green.This is a visual indication to the forktruck operator that things in thevicinity of the forktruck are safe, and a visual indication to others inthe facility (if in a line of sight where they can see the color) that asafe condition exists. Once a hazardous situation or potential isdetected, the light array 300 projects a different color, for example,the color red. Again, this serves as a conspicuous visual indication tonot only the forktruck driver, but also to potentially affectedpedestrians in the vicinity. This light signal can also be modulatedusing techniques previously described. For example, the shape of aprojected red light signal could be modulated by forktruck speed orturning status to be relatively larger in a direction of greaterpotential danger.

Another communication mode that benefits from enhanced conspicuity isthe tactile mode. While most tactile communication is personal already(since the sense of touch does not extend beyond the body like thesenses of sight and hearing), conspicuity could be enhanced byconducting physiological studies to determine the parts of the body thatare the most sensitive to tactile stimuli (vibration, slight electricshock, heat, cold, etc). Without the benefit of such studies, onethought is to incorporate tactile communication into apparel alreadyworn by people in industrial environments (e.g. safety vests, hard hats,safety glasses).

A communication mode that is related to tactile sensation is forktruckspeed. If determination of a dangerous situation by a sensing and hazarddiscrimination system (e.g. a pedestrian in close proximity, passage ofthe forktruck through a doorway, a forktruck backing out of a trailerwith a pedestrian in the loading dock vicinity) resulted in the speed ofthe forktruck being reduced (perhaps to zero), that reduction in speedwould serve as a tactile indication to the forktruck driver of thedangerous condition. Interestingly, the reduction in speed could wellserve as a visual warning to pedestrians in the vicinity that adangerous condition existed—dangerous enough to cause an automatic speedreduction of the forktruck. Combining that reduction is speed withanother mode or warning (e.g. an aural or light-based visual warning)could be even more effective.

In yet other examples, enhancing warning conspicuity is combined withexisting (and perhaps improved as described above) modes of warning. Asshown in FIG. 15, a hard hat 400 provides a plurality of (e.g., three)different modes of warning. Earphones 410 are incorporated into the hat400 to provide an aural warning capability. Tactile sources 420 aremounted to the interior of the hat 400 to engage the head of the wearerand convey tactile signals (e.g. vibration, slight electric stimulation,heat, cold). The hard hat 400 also includes integral safety glasses 430with some form of light-up or heads-up display feature to provideconspicuous visual warning to the wearer. As an alternative, the hardhat 400 could provide just visual and aural warnings, while tactilesources embedded in a vest or other article of apparel could providetactile warnings. To facilitate such an arrangement, a network could becreated on the person, for example, by including Zigbee transponders (ortransponders capable of wireless communication through other or similarprotocols) in both the vest and the hard hat 400.

Regardless of how such multi-mode warnings are implemented in hardware,the presence of multiple warning modes presents opportunities forenhancing the conspicuity of the warnings generated thereby. Oneenhancement is provided by how the various modes of warning are stagedfor the increasing severity of imminence of a threat. Low-level warnings(intended to raise awareness as opposed to empower action) can beprovided by a first of the modes—for example tactile. The next level ofwarning (increased imminence of the dangerous situation) can be providedby a second mode—for example aural. Finally, the highest level ofwarning (for an imminent potentially catastrophic event like acollision) can be a third mode such as a visual warning. Appropriatetraining is provided to personnel to recognize the threat hierarchyrepresented by the various threat-communication modes: in this examplevibration of tactile sources means “be aware,” aural warnings mean “beprepared to take action,” and visual warnings mean “take corrective oravoidive action immediately.”

Another alternative to the previous example where the variouscommunication modes were used serially as threat imminence increased, isto use the modes in parallel or at least in combinations to enhanceconspicuity. In some examples, the modes are used in an additivefashion. The first level of warning uses one mode (e.g. tactilewarning), while the second adds another mode (e.g. visual mode).Finally, for the highest level of warning, all three modes are usedtogether adding an aural warning. This example presumes only threelevels of warning and indeed that there are warning levels at all, asopposed to just conveying different hazards with different combinationsof modes, which is also a feature that can be provided by a multi-modewarning scheme. The scheme may also be used with different combinationsof modes being intended to convey different warnings. Tactile/Visual maymean one warning while Tactile/Aural means another warning and so on.Providing a system with the hardware for multi-mode warnings, as well asthe ability to control that hardware to present various combinations andsequences of warnings across those modes will enhance the conspicuity ofthose warnings. Determining the appropriate multi-mode warningmethodology to achieve the desired conspicuity can be facilitated byconducting clinical human responsiveness studies. The results of suchstudies could reveal the optimal multi-mode warning methodology forgiven hazardous situations, or reveal optimal warning methodology forthe individual warning modes described above.

Another example to enhance communication channel conspicuity is toprovide a system with the ability to make sure that the communicationchannel being used can be sensed above the background signals alreadypresent in that channel. As mentioned before, the industrial environmentis full of both visual and aural warnings, as well as lights and soundsfrom machinery, plant operations, material handling and the like.Accordingly, a feature of a conspicuous aural mode warning system isincluding a sound pressure level (SPL) measuring device for determiningthe level of background noise above which an alarm must be heard. Anexample of a hard hat with such an SPL 501 is depicted in FIG. 16. Thehard hat 500 also includes integral headphones 510. Finally, a controldevice in the form of a functional block 520 is provided. The controldevice is capable of accepting the output of the SPL (the backgroundnoise level) and outputting the appropriate aural warning signal at avolume 15-25 dB above the background noise level. 15-25 dB has beendetermined by physiological studies to be the optimum level aboveambient noise to ensure that the warning will be heard, without being soloud that the listener will shut off the alarm. It is also desirable inthe context of a multi-mode warning system for a reasonable upper limitto be set in the control device 520 to ensure that hearing-harmfullevels of sound are not presented to the wearer. In that situation, thecontrol device 520 is programmed to use different communication mode(s)to convey the warning. In a similar vein, the same hard hat 500 can alsobe provided with a longitudinally-extending light source 540 under thebill of the hat. In that case, the control device 520 or sensor 501 isable to sense ambient light levels (such as with a light-level dependentresistor) and output a light level of the light source 540 that issufficiently above the ambient light level to be seen by the wearer.

The conspicuity of threat communication is also enhanced by modulatingthe threat communication based on the imminence of the threat.Regardless of the mode (or modes) of threat-communication, the signal ismodulated to convey a different signal as the threat imminenceincreases. An example of this in the context of an aural warning isvolume. As the threat becomes more imminent, the volume of the warningincreases. The pitch of an aural warning (whether a single tone, or acomplex audio signal like speech) could also be modulated in thisfashion. For a repeated aural warning, the periodicity of the repetitioncan be modulated to convey increasing threat imminence presumably withshorter cycles indicating more immediate danger. Rhythm could also bemodulated for a multi-beat sound, for example with greater syncopationof the beat being indicative of a more imminent threat. Moreover, one orseveral of these forms of modulation could be combined to furtherenhance conspicuity. Supplying all of these modulation elements togethercould make the warning signal into something akin to a musical signal. Acolloquial example of these various aural modulations combining toconvey the rising imminence of a threat is the theme music to the film“Jaws”. Tempo, rhythm, volume and pitch are all modulated to convey thedanger of the shark drawing closer and finally striking. This music isclearly conspicuous to the listener, and using similar modulationtechniques can make aural warnings in the industrial setting equally asconspicuous.

In a similar vein, the other threat-communication modes can be modulatedby threat imminence in a similar manner. For the visual mode,brightness, color and flash rate are synonymous with volume, pitch andtempo (repetition rate) for sound and the rhythm of the light can alsobe modulated. Indeed, both sound and light could be modulated (in eitherthe same or different ways) with increasing threat imminence. Forexample, tone warnings and light flash warning could be simultaneous forlow threat levels, but have some level of alternation or indeedsyncopation for high threat levels. Tactile sensations could besimilarly modulated again either in isolation or in combination withother threat communication modes.

While the imminence of a threat is an aspect of the threat that can bespecified in the warning(s) presented to the endangered person,additional aspects of the threat can also be conveyed to enhance threatcommunication. Several examples of threat-specified warnings will bepresented below. One theme of threat-specified warnings is to provideenough information to the endangered person to empower that person (e.g.a pedestrian under threat of being struck by a forktruck) with adequateinformation about the nature of the threat so as to allow him theability to exercise judgment in either avoiding the hazard orextricating himself from the dangerous condition. For the purposes ofthese examples, techniques based on aural (sound) communication will bepresented. As show above, however, issuing warning communications inmultiple modes (e.g. aural, visual and tactile) may be beneficial, andthose additional kinds of warnings could also be employed to conveythreat-specified warnings. Moreover, all of the examples related towarnings for the example “endangered person” of a threatened pedestriancould apply equally to other people involved in the situation, such asforktruck (or other vehicle) operators, bystanders, etc.

In the area of threat-specified aural warnings, improvement can be madeto conventional warnings. Referring to the example of a pedestrianequipped with an RF receiver capable of receiving and decoding RFsignals transmitted by a forktruck, a conventional system might providesome warning to the pedestrian when the signal strength rises above acertain threshold indicative of a dangerous proximity of the forktruck.Such a warning conveys only limited information, and may not be adequateto allow the pedestrian to take effective corrective or avoidive action.Rather, a more effective communication of that threat would conveysomething about its nature. For example, assume that either: 1) theforktruck has the ability to transmit an RF signal modulated by itsstate of movement (the transmitted signals are different when theforktruck is stationary versus when it is moving, and indicative of thespeed and direction of the movement) or 2) that the receiver on thepedestrian has the ability to make such determinations based on thesignal(s) received from the forktruck, or a combination of thesefunctionalities. Under that assumed scenario, a threat-specified warningwould provide different actual warning based on whether the forktruckwas moving toward the pedestrian, or whether the forktruck wasstationary and the pedestrian simply moved close enough to be within aproximity that would otherwise be dangerous if the forktruck were notstationary. For the less dangerous situation of a pedestrian movingclose to a stationary forktruck, no warning might be given at all.Alternatively, a warning to raise the awareness of the pedestrian mightbe given since he is close to the forktruck and it might begin moving atany time. For a moving forktruck approaching dangerously close to apedestrian, a higher level warning of imminent danger might becommunicated. If the warnings are communicated to the pedestrianaurally, these different warnings (or indications of corrective action)for different levels of threat could be produced in a variety of ways.In one scenario, several warnings for several different threats havebeen recorded in some medium and are carried with the pedestrian. Anexample might be an MP3 player with prerecorded tracks. A unit capableof processing either signals sent from the forktruck modulated withthreat-specific information or capable of translating unmodulatedsignals from the forktruck to determine the threat itself would also becapable of determining which warning should be conveyed to thepedestrian. Track 1 of the MP3 player might be “You are in dangerousproximity to a stopped forktruck—use caution”, while track 2 might be“DANGER—Forktruck rapidly approaching—collision possible!” Depending onthe threat-specific information determined by the processor, it wouldoutput a control command to the MP3 player to play the prerecorded trackrelevant to the determined danger. In other examples, a processor can beprovided with a broad possible vocabulary (for example 50 or 100 wordsthat could be used in warning in the context of interest), and logic forformulating warnings would string together such words depending upon thenature of the threat the processor determines. This would allow thespecificity of the threat-warning to be increased, particularly forcases where more accurate and detailed threat information can beconveyed to the processor by the hazard sensing and/or locating systemsdescribed above. Moreover, the vocabulary could be dynamically modifiedover time to keep the warnings “fresh” to the listener.

Other types of threat-specified information can be conveyed to anendangered pedestrian besides the existence or specific nature of athreat, or the imminence of the danger. For a sensing/location systemcapable of determining imminence of a threat, the identity of theforktruck driver could be useful information to the endangeredpedestrian. Rather than simply receiving a warning like “Forktruckapproaching—collision possible”, one could receive the warning “JohnSmith's forktruck approaching in 5 seconds”. If experience tells thepedestrian that John Smith's safety record or driving habits are poor,the receipt of such threat-specific information may allow the pedestrianto take more effective or swift corrective action. Type of informationconveyed in some examples include whether the forktruck is loaded ornot. The sight lines for the driver of a loaded forktruck are much morelimited than an unloaded truck, and knowing that the truck is loaded mayagain suggest to the pedestrian that he should treat the threat moreseriously. Similarly, it could be useful to the pedestrian to knowwhether the forktruck was traveling in a forward or rearward direction.Again, the sight lines for a backing forktruck are much more limitedthan for a traveling forktruck, and this information might be relevantto an endangered pedestrian.

The threat-specificity of the warning being conveyed to an entity ofinterest can also be improved by including location-specific ordirection-specific information about the threat. If an endangeredindividual, such as a pedestrian in danger of being struck by aforktruck, is told either the direction from which the threat is coming,or the direction of escape from the threat, his response will likely bemore effective than if this information is not received. While thebenefit of this information is manifest, the means for implementing isnot. Part of the difficulty lies in the relative nature of direction.For example, if a pedestrian is facing north, and a forktruck isapproaching eastbound from the west, or that the forktruck isapproaching on the pedestrian's left. But for the same eastboundforktruck approaching a pedestrian facing south, the forktruck isapproaching the pedestrian's right. Directionality in this sense is thusa function of the orientation of the pedestrian. A location or directionspecific warning would need to overcome this complication.

Some examples provide the warning system of an endangered individual(e.g. a pedestrian) with compass capability, and for the threat signalprovided to that warning system to include the compass orientation ofthe threat. In this scenario, the warning system is presented with twodata points regarding the threat: 1) the current orientation of thepedestrian; and 2) the direction of the approaching threat (e.g. aforktruck). For a pedestrian facing due south (compass direction 180degrees) and an eastbound forktruck (compass direction 270 degrees), thewarning system would determine that a clockwise rotation of 90 degreeswould reveal the threat to the pedestrian. Assuming the pedestrian wereequipped with a threat-communication system including a right channeland a left channel (e.g. right and left ear phones, or right and leftlight-up eyeglasses), the right channel is activated in this example toindicate to the pedestrian that a threat is approaching from the right.Activating the right channel for the purpose either of getting thepedestrian's attention and causing him to turn to the right to see thehazard, or to get him to move away from the right orientation since thatis the locus of the threat. The imminence of the threat may indicatewhich of these actions is preferable, so the warning may convey not onlythe orientation of the threat, but also its imminence, thereby allowingthe pedestrian to consider the warning and take appropriate action.

For a threat of relatively low imminence of danger (e.g. a forktruckapproaching a pedestrian, but still 30 feet away), thedirection-specificity of the warning signal may be modulated by therelative difference of the pedestrian's orientation and that of thethreat. Staying with the previous example, detection of the pedestrianat orientation 180 and the threat at orientation 270 gives a signal tothe right communication channel of the pedestrian. As he begins rotatingtoward the 270 orientation, and reducing the angle between hisorientation and the threat's, the warning signal could be modulated, forexample, with the repetition rate of an aural signal increasing as thepedestrian gets closer to the threat orientation. Similarly, if he turnstoward the wrong orientation, the repetition rate would go down. Astereophonic system could also be used to convey directionality to theuser.

Another alternative for implementing direction or location specificationto a warning signal is to provide a potentially threatened individualwith multiple position indicators. Since indicators numbering beyond twomight be problematic for our stereo senses (sight and sound), thisexample may be implemented in the tactile sense, since it is not subjectto this limitation. Accordingly, a potentially threatened person isprovided with four position indicators in the form of tactilestimulators, illustratively representing left, right, front and back.For a centralized hazard discrimination system capable of distinguishingthe location of each of the four position indicators, a warning signalis formulated to only stimulate the indicator or indicators in closestproximity to the hazard. Returning to the south-facing pedestrian andthe eastbound forktruck, the hazard discriminator would only stimulatethe “right” indicator to indicate the approach vector of the threat. If,however, the forktruck were approaching from 315 degrees (toward 135degrees), the hazard discriminator send a warning signal stimulatingboth the “right” and “back” sensors equally. For approach angles between270 and 315, greater stimulation level might be provided to the “right”indicator than to the “back” indicator, assuming that the tactile sensecan adequately distinguish such stimulation levels. Another option is toprovide an array of stimulators around the perimeter of the pedestrian'sbody to be able to use the same approach to achieve greater angularspecificity. As with the aural warning, the tactile warning might bemodulated as the orientation of the pedestrian approaches theorientation of the threat.

A similar directionality can also be conveyed to the pedestrian even ifthere is not a centralized hazard discrimination system. In thisexample, the pedestrian carries the four tactile position indicators,but also carries a similarly-oriented array of four detectors. Toprovide warning signals, an approaching forktruck emits a repeatingsignal in a forward direction that can be detected by the four detectorson the pedestrian. Control electronics allow the repeating signal to bereceived by the four detectors, and resolved to determine the directionof approach of the forktruck. For example, if the pedestrian is facingnorth, the four detectors are facing the compass points. For asouthbound forktruck, the north detector would detect the signal first,followed by a simultaneous detection by the east and west detectors, andfinally followed by a detection by the south detector. For the sameorientation of the pedestrian, a forktruck approaching on a 45 degreepath (toward 225 degrees) would result in a simultaneous detection bythe north and east detectors, followed by a simultaneous detection bythe south and west detectors. In short, an operation could be programmedinto the control electronics to be able to resolve the direction of thethreat from any angle. In a similar vein, the control electronics couldthen control the tactile position indicators to convey the determineddirectionality to the affected pedestrian. In some examples, the fourdetectors have the same orientation as the four stimulators, and thecontrol electronics are programmed to first determine the orientation ofthe threat, and then to stimulate either one or two stimulators toconvey that threat orientation. In the case of a threat oriented fromthe north in our example, only the stimulator in that orientation isactivated—but for the threat on a 45 degree vector, both the north andeast stimulators are activated. This system has the benefit that it canbe implemented without regard for the compass orientation of thepedestrian. If he is facing south instead of north in our example, hisback and left stimulators are activated for a forktruck approaching on a45 degree vector, as opposed to his right and front stimulators if herewere facing north for the same forktruck approach. Moreover, the exampleis not limited to 4 detectors or stimulators, and more of either couldimprove accuracy.

Some example methods and apparatus described herein not only improve theconspicuity of the warnings that are or can be used for conveyingthreats, but also improve the content of threat communication. Thoseimprovements include specifying the imminence of the threat, the natureof the threat, relevant details of the threat (e.g. the identity of theapproaching forktruck driver, or whether he was carrying a load or not),and/or details about the direction or location of the threat relative tothe affected pedestrian. These threat communication enhancements areintended, among other goals, to provide the affected pedestrian withconspicuous and meaningful warnings to not only get his attention, butalso to provide him with necessary information to allow him to exercisejudgment and take corrective action relative to the now-known threat.

FIG. 17 is a block diagram of an example processing system 1700 capableof executing the machine readable instructions represented by FIGS. 4C,6C, 8 and/or 9C to implement the apparatus and methods disclosed herein.The processing system 1700 can be, for example, a server, a personalcomputer, or any other type of computing device.

The example system 1700 of FIG. 17 includes a processor 1712. Forexample, the processor 1712 can be implemented by one or more Intel®microprocessors from the Pentium® family, the Itanium® family or theXScale® family. Of course, other processors from other families are alsoappropriate.

The processor 1712 is in communication with a main memory including avolatile memory 1714 and a non-volatile memory 1716 via a bus 1718. Thevolatile memory 1714 may be implemented by Synchronous Dynamic RandomAccess Memory (SDRAM), Dynamic Random Access Memory (DRAM), RAMBUSDynamic Random Access Memory (RDRAM) and/or any other type of randomaccess memory device. The non-volatile memory 1716 may be implemented byflash memory and/or any other desired type of memory device. Access tothe main memory 1714, 1716 is typically controlled by a memorycontroller (not shown).

The computer 1700 also includes an interface circuit 1720. The interfacecircuit 1720 may be implemented by any type of interface standard, suchas an Ethernet interface, a universal serial bus (USB), and/or a PCIexpress interface.

One or more input devices 1722 are connected to the interface circuit1720. The input device(s) 1722 permit a user to enter data and commandsinto the processor 1712. The input device(s) can be implemented by, forexample, a keyboard, a mouse, a touchscreen, a track-pad, a trackball,isopoint and/or a voice recognition system.

One or more output devices 1724 are also connected to the interfacecircuit 1720. The output devices 1724 can be implemented, for example,by display devices (e.g., a liquid crystal display, a cathode ray tubedisplay (CRT), a printer and/or speakers). The interface circuit 1720,thus, typically includes a graphics driver card.

The interface circuit 1720 also includes a communication device (e.g.,communication device 72 a, b) such as a wireless transmitter, WiFiconnection, modem or network interface card to facilitate exchange ofdata with external computers via a wired or wireless network (e.g., anEthernet connection, a digital subscriber line (DSL), a telephone line,coaxial cable, a cellular telephone system, etc.).

The computer 1700 also includes one or more mass storage devices 1728for storing software and data. Examples of such mass storage devices1728 include floppy disk drives, hard drive disks, compact disk drivesand digital versatile disk (DVD) drives.

The coded instructions of FIGS. 6C, 8, 9C, 10B and/or 10C may be storedin the mass storage device 1728, in the volatile memory 1714, in thenon-volatile memory 1716, and/or on a removable storage medium such as aCD or DVD 1730.

Although this patent discloses example systems including software and/orfirmware executed on hardware, it should be noted that such systems aremerely illustrative and should not be considered as limiting. Forexample, it is contemplated that any or all of these hardware andsoftware components could be embodied exclusively in hardware,exclusively in software, exclusively in firmware or in some combinationof hardware, firmware and/or software. Accordingly, while the abovespecification described example systems, methods and articles ofmanufacture, the examples are not the only way to implement suchsystems, methods and articles of manufacture. Therefore, althoughcertain example methods, apparatus and articles of manufacture have beendescribed herein, the scope of coverage of this patent is not limitedthereto. On the contrary, this patent covers all methods, apparatus andarticles of manufacture fairly falling within the scope of the appendedclaims either literally or under the doctrine of equivalents.

What is claimed is:
 1. A warning signal generation system comprising: aselector to select between different modes of movement for a vehicle,the different modes of movement including at least a forward position toenable the vehicle to move in a forward direction and a rearward mode toenable the vehicle to move in a rearward direction; a detector todetermine which of the different modes of movement has been selected viathe selector and to produce an output indicative of that mode ofmovement; and a signal generator including an input to receive theoutput indicative of the vehicle mode of movement from the detector, thesignal generator to generate a selected signal based on the receivedoutput indicative of the mode of movement of the vehicle, the selectedsignal to represent a warning zone proximate the vehicle based on adirection of movement of the vehicle indicated by the detected mode ofmovement of the vehicle, the signal generator to change a direction ofthe selected signal based on a change in the mode of movement detectedby the detector, and the signal generator to modify a size and a shapeof the warning zone based on a speed of the vehicle, the selected signalto communicate with a device separate from the vehicle and within thewarning zone.
 2. A signal generation system as in claim 1, wherein themodes of movement of the vehicle further includes a stationary position.3. A signal generation system as in claim 2, wherein the selected signalgenerates the warning zone in a forward direction relative to vehicletravel when the forward position is selected via the selector.
 4. Asignal generation system as in claim 1, wherein the selected signal isat least one of a form of a magnetic signal, a RF signal, an opticalsignal, or an infrared signal.
 5. A signal generation system for avehicle capable of different modes of movement, the generation systemcomprising: a detector to determine a property of vehicle movement andto produce an output representative of the property, the property ofvehicle movement being a dynamic property including a forward directionand a rearward direction; and a signal generator including an input toreceive the output representative of the property of vehicle movementfrom the detector, the signal generator to generate a first selectedsignal that provides a first warning zone that is directed toward afront of the vehicle when the detector detects the vehicle is moving inthe forward direction and a second selected signal that provides asecond warning zone that is directed toward a rear of the vehicle whenthe vehicle is moving in the rearward direction, the signal generator todynamically modify a size and shape of the first and second warningzones based on the property of vehicle movement as the vehicle movesalong a travel path, the signal generator to select between the firstselected signal and the second selected signal based on a detectedchange in direction of the vehicle, the first and second selectedsignals to communicate with a device separate from the vehicle andwithin the first and second warning zones.
 6. The signal generationsystem of claim 5, wherein the dynamic property further includes a speedof the vehicle.
 7. The signal generation system of claim 5, wherein thedynamic property includes a position of a vehicle steering wheel.
 8. Thesignal generation system of claim 5, wherein the dynamic propertyincludes a rotational direction in which a vehicle steering wheel isbeing rotated.
 9. A signal generation system for a vehicle capable ofdifferent modes of movement, the generation system comprising: adetector to determine a property of vehicle movement and to produce anoutput representative of the property, the property of vehicle movementbeing a dynamic property including at least one of a forward directionand a rearward direction; and a signal generator including an input toreceive the output representative of the property of vehicle movementfrom the detector and, responsively, to generate a selected signal basedon the received output, wherein the selected signal provides a warningzone that is directed toward a front of the vehicle when the vehicle ismoving in the forward direction and directed toward a rear of thevehicle when the vehicle is moving in the rearward direction, theselected signal to communicate with a device separate from the vehicleand within the warning zone, wherein the dynamic property is arotational direction in which a vehicle steering wheel is being rotated,and wherein the selected signal projects the warning zone in a directionopposite the rotational direction in which the vehicle steering wheel isrotated.
 10. The signal generation system of claim 9, wherein thedynamic property further comprises a vehicle selector being engaged inat least one of a forward position or a rearward position.
 11. Thesignal generation system of claim 9, further comprising a plurality ofdetectors, each of the detectors to determine the property of vehiclemovement and to produce a property-representative output, and the signalgenerator to generate the selected signal based on theproperty-representative outputs from the detectors.
 12. The signalgeneration system of claim 9, wherein the selected signal is light. 13.The signal generation system of claim 12, wherein a color of the lightis selected based on the received input.
 14. The signal generationsystem of claim 1, wherein the shape of the warning zone provided by theselected signal changes based on the mode of movement of the vehicle.15. The signal generation system of claim 14, wherein the shape of thewarning zone radiates only in front of the vehicle when the vehicle ismoving in a forward direction.
 16. The signal generation system of claim1, wherein the selected signal is a proximity signal broadcast by atransmitter of the vehicle.
 17. The signal generation system of claim 1,wherein the selected signal is to be detected by a receiver positionedwithin the warning zone.
 18. The signal generation system of claim 1,wherein the selected signal is generated based on a gear selection ofthe vehicle provided by the selector.
 19. The signal generation systemof claim 2, wherein the selected signal provides the warning zone whenthe mode of movement is stationary.
 20. The signal generation system ofclaim 19, wherein the warning zone generated by the selected signalradiates in all directions relative to the vehicle when the mode ofmovement is stationary.
 21. The signal generation system of claim 20,wherein the warning zone has a circular profile when the mode ofmovement is stationary.
 22. The signal generation system of claim 2,wherein the selected signal generates the warning zone in a rearwarddirection relative to vehicle travel when reverse is the mode ofmovement.
 23. The signal generation system of claim 2, wherein theselected signal generates the warning zone having a non-circular profilewhen at least one of forward or reverse is the mode of movement.
 24. Thesignal generation system of claim 1, wherein the warning zone projects afirst distance when the vehicle is traveling at a first speed and thewarning zone projects a second distance when the vehicle is traveling ata second speed, the first distance being greater than the seconddistance when the first speed is greater than the second speed.